diff --git a/ANNOUNCE b/ANNOUNCE
index a10ab69a5..5fe531084 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.0.9beta5 - December 15, 2000
+Libpng 1.0.9beta6 - December 18, 2000
 
 This is a public release of libpng, intended for use in production codes.
 
@@ -35,6 +35,15 @@ Changes since the last public release (1.0.8):
   Change png_chunk_warning to png_warning in png_check_keyword().
   Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
   Added support for filter method 64 (for PNG datastreams embedded in MNG)
+  Revised png_set_filter() to accept filter method 64 when appropriate.
+  Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
+    help prevent applications from using MNG features in PNG datastreams.
+  Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
+
+Send comments/corrections/commendations to
+png-implement@ccrc.wustl.edu or to randeg@alum.rpi.edu
+
+Glenn R-P
 
 Send comments/corrections/commendations to
 png-implement@ccrc.wustl.edu or to randeg@alum.rpi.edu
diff --git a/CHANGES b/CHANGES
index 7fa8fa6ce..3bc332116 100644
--- a/CHANGES
+++ b/CHANGES
@@ -857,6 +857,11 @@ version 1.0.9beta4 [December 1, 2000]
   Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
 version 1.0.9beta5 [December 15, 2000]
   Added support for filter method 64 (for PNG datastreams embedded in MNG)
+version 1.0.9beta6 [December 18, 2000]
+  Revised png_set_filter() to accept filter method 64 when appropriate.
+  Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
+    help prevent applications from using MNG features in PNG datastreams.
+  Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
 
 Send comments/corrections/commendations to
 png-implement@ccrc.wustl.edu or to randeg@alum.rpi.edu
diff --git a/INSTALL b/INSTALL
index ce0984cfe..cfa0451da 100644
--- a/INSTALL
+++ b/INSTALL
@@ -1,5 +1,5 @@
 
-Installing libpng version 1.0.9beta5 - December 15, 2000
+Installing libpng version 1.0.9beta6 - December 18, 2000
 
 Before installing libpng, you must first install zlib.  zlib
 can usually be found wherever you got libpng.  zlib can be
@@ -10,7 +10,7 @@ zlib.h and zconf.h include files that correspond to the
 version of zlib that's installed.
 
 You can rename the directories that you downloaded (they
-might be called "libpng-1.0.9beta5" or "lpng109" and "zlib-1.1.3"
+might be called "libpng-1.0.9beta6" or "lpng109" and "zlib-1.1.3"
 or "zlib113") so that you have directories called "zlib" and "libpng".
 
 Your directory structure should look like this:
@@ -59,8 +59,8 @@ The files that are presently available in the scripts directory
 include
 
  makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
- makefile.linux    =>  Linux/ELF makefile (gcc, creates libpng.so.2.1.0.9beta5)
- makefile.gcmmx    =>  Linux/ELF makefile (gcc, creates libpng.so.2.1.0.9beta5,
+ makefile.linux    =>  Linux/ELF makefile (gcc, creates libpng.so.2.1.0.9beta6)
+ makefile.gcmmx    =>  Linux/ELF makefile (gcc, creates libpng.so.2.1.0.9beta6,
                        uses assembler code tuned for Intel MMX platform)
  makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
  makefile.knr      =>  Archaic UNIX Makefile that converts files with
@@ -75,9 +75,9 @@ include
  libpng.icc        =>  Project file for IBM VisualAge/C++ version 4.0 or later
  makefile.macosx   =>  MACOS X Makefile
  makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
- makefile.sggcc    =>  Silicon Graphics (gcc, creates libpng.so.2.1.0.9beta5)
+ makefile.sggcc    =>  Silicon Graphics (gcc, creates libpng.so.2.1.0.9beta6)
  makefile.sunos    =>  Sun makefile
- makefile.solaris  =>  Solaris 2.X makefile (gcc, creates libpng.so.2.1.0.9beta5)
+ makefile.solaris  =>  Solaris 2.X makefile (gcc, creates libpng.so.2.1.0.9beta6)
  makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
  makefile.mips     =>  MIPS makefile
  makefile.acorn    =>  Acorn makefile
diff --git a/LICENSE b/LICENSE
index 842384bc5..b7f1dd92a 100644
--- a/LICENSE
+++ b/LICENSE
@@ -8,7 +8,7 @@ COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.0.7, July 1, 2000, through 1.0.9beta5, December 15, 2000, are
+libpng versions 1.0.7, July 1, 2000, through 1.0.9beta6, December 18, 2000, are
 Copyright (c) 2000 Glenn Randers-Pehrson
 and are distributed according to the same disclaimer and license as libpng-1.0.6
 with the following individuals added to the list of Contributing Authors
@@ -99,4 +99,4 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 randeg@alum.rpi.edu
-December 15, 2000
+December 18, 2000
diff --git a/README b/README
index bfdaf4015..e6b072f6d 100644
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-README for libpng 1.0.9beta5 - December 15, 2000 (shared library 2.1)
+README for libpng 1.0.9beta6 - December 18, 2000 (shared library 2.1)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
@@ -182,9 +182,9 @@ Files in this distribution:
        descrip.mms      =>  VMS makefile for MMS or MMK
        makefile.std     =>  Generic UNIX makefile (cc, creates static libpng.a)
        makefile.linux   =>  Linux/ELF makefile
-                            (gcc, creates libpng.so.2.1.0.9beta5)
+                            (gcc, creates libpng.so.2.1.0.9beta6)
        makefile.gcmmx   =>  Linux/ELF makefile (gcc, creates
-                            libpng.so.2.1.0.9beta5, uses assembler code
+                            libpng.so.2.1.0.9beta6, uses assembler code
                             tuned for Intel MMX platform)
        makefile.gcc     =>  Generic makefile (gcc, creates static libpng.a)
        makefile.knr     =>  Archaic UNIX Makefile that converts files with
@@ -199,10 +199,10 @@ Files in this distribution:
        libpng.icc       =>  Project file, IBM VisualAge/C++ 4.0 or later
        makefile.macosx  =>  MACOS X Makefile
        makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
-       makefile.sggcc   =>  Silicon Graphics (gcc, creates libpng.so.2.1.0.9beta5)
+       makefile.sggcc   =>  Silicon Graphics (gcc, creates libpng.so.2.1.0.9beta6)
        makefile.sunos   =>  Sun makefile
        makefile.solaris =>  Solaris 2.X makefile
-                            (gcc, creates libpng.so.2.1.0.9beta5)
+                            (gcc, creates libpng.so.2.1.0.9beta6)
        makefile.sco     =>  For SCO OSr5  ELF and Unixware 7 with Native cc
        makefile.mips    =>  MIPS makefile
        makefile.acorn   =>  Acorn makefile
diff --git a/Y2KINFO b/Y2KINFO
index ae353783a..c2fef40fe 100644
--- a/Y2KINFO
+++ b/Y2KINFO
@@ -1,13 +1,13 @@
    Y2K compliance in libpng:
    =========================
 
-      December 15, 2000
+      December 18, 2000
 
       Since the PNG Development group is an ad-hoc body, we can't make
       an official declaration.
 
       This is your unofficial assurance that libpng from version 0.71 and
-      upward through 1.0.9beta5 are Y2K compliant.  It is my belief that earlier
+      upward through 1.0.9beta6 are Y2K compliant.  It is my belief that earlier
       versions were also Y2K compliant.
 
       Libpng only has three year fields.  One is a 2-byte unsigned integer
diff --git a/configure b/configure
index 0f33682e0..a4ec3840b 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 echo "
-  There is no \"configure\" script for Libpng-1.0.9beta5.  Instead, please
+  There is no \"configure\" script for Libpng-1.0.9beta6.  Instead, please
   copy the appropriate makefile for your system from the \"scripts\"
   directory.  Read the INSTALL file for more details.
 "
diff --git a/libpng.3 b/libpng.3
index b515fb5d0..2fb76aed4 100644
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "December 15, 2000"
+.TH LIBPNG 3 "December 18, 2000"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta5
+libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta6
 .SH SYNOPSIS
 \fI\fB
 
@@ -747,7 +747,7 @@ Following is a copy of the libpng.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.0.9beta5 - December 15, 2000
+ libpng version 1.0.9beta6 - December 18, 2000
  Updated and distributed by Glenn Randers-Pehrson
  <randeg@alum.rpi.edu>
  Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
@@ -1147,7 +1147,7 @@ in until png_read_end() has read the chunk data following the image.
 
     png_get_IHDR(png_ptr, info_ptr, &width, &height,
        &bit_depth, &color_type, &interlace_type,
-       &compression_type, &filter_type);
+       &compression_type, &filter_method);
 
     width          - holds the width of the image
                      in pixels (up to 2^31).
@@ -1175,15 +1175,18 @@ in until png_read_end() has read the chunk data following the image.
                      PNG_COLOR_MASK_COLOR
                      PNG_COLOR_MASK_ALPHA
 
-    filter_type    - (must be PNG_FILTER_TYPE_BASE
-                     for PNG 1.0)
+    filter_method  - (must be PNG_FILTER_TYPE_BASE
+                     for PNG 1.0, and can also be
+                     PNG_INTRAPIXEL_DIFFERENCING if
+                     the PNG datastream is embedded in
+                     a MNG-1.0 datastream)
     compression_type - (must be PNG_COMPRESSION_TYPE_BASE
                      for PNG 1.0)
     interlace_type - (PNG_INTERLACE_NONE or
                      PNG_INTERLACE_ADAM7)
     Any or all of interlace_type, compression_type, of
-                     filter_type can be NULL if you are not
-                     interested in their values.
+                     filter_method can be NULL if you are
+                     not interested in their values.
 
     channels = png_get_channels(png_ptr, info_ptr);
     channels       - number of channels of info for the
@@ -1213,7 +1216,7 @@ in until png_read_end() has read the chunk data following the image.
                          info_ptr);
     color_type       = png_get_color_type(png_ptr,
                          info_ptr);
-    filter_type      = png_get_filter_type(png_ptr,
+    filter_method    = png_get_filter_type(png_ptr,
                          info_ptr);
     compression_type = png_get_compression_type(png_ptr,
                          info_ptr);
@@ -2286,10 +2289,11 @@ maximum possible compression at the expense of slower writing.  If you
 have no special needs in this area, let the library do what it wants by
 not calling this function at all, as it has been tuned to deliver a good
 speed/compression ratio. The second parameter to png_set_filter() is
-the filter method, for which the only valid value is '0' (as of the
-July 1999 PNG specification, version 1.2).  The third parameter is a
-flag that indicates which filter type(s) are to be tested for each
-scanline.  See the PNG specification for details on the specific filter
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream).  The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline.  See the PNG specification for details on the specific filter
 types.
 
 
@@ -2310,6 +2314,9 @@ it should start out with all of the filters (to ensure that the previous
 row of pixels will be stored in case it's needed later), and then add
 and remove them after the start of compression.
 
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
 The png_set_compression_*() functions interface to the zlib compression
 library, and should mostly be ignored unless you really know what you are
 doing.  The only generally useful call is png_set_compression_level()
@@ -2348,7 +2355,7 @@ Some of the more important parts of the png_info are:
 
     png_set_IHDR(png_ptr, info_ptr, width, height,
        bit_depth, color_type, interlace_type,
-       compression_type, filter_type)
+       compression_type, filter_method)
     width          - holds the width of the image
                      in pixels (up to 2^31).
     height         - holds the height of the image
@@ -2380,7 +2387,11 @@ Some of the more important parts of the png_info are:
                      PNG_INTERLACE_ADAM7
     compression_type - (must be
                      PNG_COMPRESSION_TYPE_DEFAULT)
-    filter_type    - (must be PNG_FILTER_TYPE_DEFAULT)
+    filter_method  - (must be PNG_FILTER_TYPE_DEFAULT
+                     or, if you are writing a PNG to
+                     be embedded in a MNG datastream,
+                     can also be
+                     PNG_INTRAPIXEL_DIFFERENCING)
 
     png_set_PLTE(png_ptr, info_ptr, palette,
        num_palette);
@@ -3217,6 +3228,10 @@ structures appropriately for all of the filter types.
 
     png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
        filters);
+              The second parameter can also be PNG_INTRAPIXEL_DIFFERENCING
+              if you are writing a PNG to be embedded in a MNG
+              datastream.  This parameter must be the same as the
+              value of filter_method used in png_set_IHDR().
 
 It is also possible to influence how libpng chooses from among the
 available filters.  This is done in two ways - by telling it how
@@ -3345,6 +3360,11 @@ png_permit_mng_features() function:
       your mask with the set of MNG features that is
       supported by the version of libpng that you are using.
 
+It is an error to use this function when reading or writing a standalone
+PNG file with the PNG 8-byte signature.  The PNG datastream must be wrapped
+in a MNG datastream (as a minimum, it must have the MNG 8-byte signature
+and the MHDR and MEND chunks).
+
 .SH VII.  Changes to Libpng from version 0.88
 
 It should be noted that versions of libpng later than 0.96 are not
@@ -3396,13 +3416,13 @@ application:
 
 .SH VIII. Y2K Compliance in libpng
 
-December 15, 2000
+December 18, 2000
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.0.9beta5 are Y2K compliant.  It is my belief that earlier
+upward through 1.0.9beta6 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
@@ -3543,7 +3563,7 @@ possible without all of you.
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.0.9beta5 - December 15, 2000:
+Libpng version 1.0.9beta6 - December 18, 2000:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (randeg@alum.rpi.edu).
 
@@ -3560,7 +3580,7 @@ included in the libpng distribution, the latter shall prevail.)
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.0.7, July 1, 2000, through  1.0.9beta5, December 15, 2000, are
+libpng versions 1.0.7, July 1, 2000, through  1.0.9beta6, December 18, 2000, are
 Copyright (c) 2000 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.0.6
 with the following individuals added to the list of Contributing Authors
@@ -3651,7 +3671,7 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 randeg@alum.rpi.edu
-December 15, 2000
+December 18, 2000
 
 .\" end of man page
 
diff --git a/libpng.txt b/libpng.txt
index 6e4c2579d..21b7aecf8 100644
--- a/libpng.txt
+++ b/libpng.txt
@@ -1,6 +1,6 @@
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.0.9beta5 - December 15, 2000
+ libpng version 1.0.9beta6 - December 18, 2000
  Updated and distributed by Glenn Randers-Pehrson
  <randeg@alum.rpi.edu>
  Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
@@ -400,7 +400,7 @@ in until png_read_end() has read the chunk data following the image.
 
     png_get_IHDR(png_ptr, info_ptr, &width, &height,
        &bit_depth, &color_type, &interlace_type,
-       &compression_type, &filter_type);
+       &compression_type, &filter_method);
 
     width          - holds the width of the image
                      in pixels (up to 2^31).
@@ -428,15 +428,18 @@ in until png_read_end() has read the chunk data following the image.
                      PNG_COLOR_MASK_COLOR
                      PNG_COLOR_MASK_ALPHA
 
-    filter_type    - (must be PNG_FILTER_TYPE_BASE
-                     for PNG 1.0)
+    filter_method  - (must be PNG_FILTER_TYPE_BASE
+                     for PNG 1.0, and can also be
+                     PNG_INTRAPIXEL_DIFFERENCING if
+                     the PNG datastream is embedded in
+                     a MNG-1.0 datastream)
     compression_type - (must be PNG_COMPRESSION_TYPE_BASE
                      for PNG 1.0)
     interlace_type - (PNG_INTERLACE_NONE or
                      PNG_INTERLACE_ADAM7)
     Any or all of interlace_type, compression_type, of
-                     filter_type can be NULL if you are not
-                     interested in their values.
+                     filter_method can be NULL if you are
+                     not interested in their values.
 
     channels = png_get_channels(png_ptr, info_ptr);
     channels       - number of channels of info for the
@@ -466,7 +469,7 @@ in until png_read_end() has read the chunk data following the image.
                          info_ptr);
     color_type       = png_get_color_type(png_ptr,
                          info_ptr);
-    filter_type      = png_get_filter_type(png_ptr,
+    filter_method    = png_get_filter_type(png_ptr,
                          info_ptr);
     compression_type = png_get_compression_type(png_ptr,
                          info_ptr);
@@ -1539,10 +1542,11 @@ maximum possible compression at the expense of slower writing.  If you
 have no special needs in this area, let the library do what it wants by
 not calling this function at all, as it has been tuned to deliver a good
 speed/compression ratio. The second parameter to png_set_filter() is
-the filter method, for which the only valid value is '0' (as of the
-July 1999 PNG specification, version 1.2).  The third parameter is a
-flag that indicates which filter type(s) are to be tested for each
-scanline.  See the PNG specification for details on the specific filter
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream).  The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline.  See the PNG specification for details on the specific filter
 types.
 
 
@@ -1563,6 +1567,9 @@ it should start out with all of the filters (to ensure that the previous
 row of pixels will be stored in case it's needed later), and then add
 and remove them after the start of compression.
 
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
 The png_set_compression_*() functions interface to the zlib compression
 library, and should mostly be ignored unless you really know what you are
 doing.  The only generally useful call is png_set_compression_level()
@@ -1601,7 +1608,7 @@ Some of the more important parts of the png_info are:
 
     png_set_IHDR(png_ptr, info_ptr, width, height,
        bit_depth, color_type, interlace_type,
-       compression_type, filter_type)
+       compression_type, filter_method)
     width          - holds the width of the image
                      in pixels (up to 2^31).
     height         - holds the height of the image
@@ -1633,7 +1640,11 @@ Some of the more important parts of the png_info are:
                      PNG_INTERLACE_ADAM7
     compression_type - (must be
                      PNG_COMPRESSION_TYPE_DEFAULT)
-    filter_type    - (must be PNG_FILTER_TYPE_DEFAULT)
+    filter_method  - (must be PNG_FILTER_TYPE_DEFAULT
+                     or, if you are writing a PNG to
+                     be embedded in a MNG datastream,
+                     can also be
+                     PNG_INTRAPIXEL_DIFFERENCING)
 
     png_set_PLTE(png_ptr, info_ptr, palette,
        num_palette);
@@ -2470,6 +2481,10 @@ structures appropriately for all of the filter types.
 
     png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
        filters);
+              The second parameter can also be PNG_INTRAPIXEL_DIFFERENCING
+              if you are writing a PNG to be embedded in a MNG
+              datastream.  This parameter must be the same as the
+              value of filter_method used in png_set_IHDR().
 
 It is also possible to influence how libpng chooses from among the
 available filters.  This is done in two ways - by telling it how
@@ -2598,6 +2613,11 @@ png_permit_mng_features() function:
       your mask with the set of MNG features that is
       supported by the version of libpng that you are using.
 
+It is an error to use this function when reading or writing a standalone
+PNG file with the PNG 8-byte signature.  The PNG datastream must be wrapped
+in a MNG datastream (as a minimum, it must have the MNG 8-byte signature
+and the MHDR and MEND chunks).
+
 VII.  Changes to Libpng from version 0.88
 
 It should be noted that versions of libpng later than 0.96 are not
@@ -2649,13 +2669,13 @@ application:
 
 VIII. Y2K Compliance in libpng
 
-December 15, 2000
+December 18, 2000
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.0.9beta5 are Y2K compliant.  It is my belief that earlier
+upward through 1.0.9beta6 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
diff --git a/libpngpf.3 b/libpngpf.3
index bb293fd82..0a8584763 100644
--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "December 15, 2000"
+.TH LIBPNGPF 3 "December 18, 2000"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta5
+libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta6
 (private functions)
 .SH SYNOPSIS
 \fB#include <png.h>\fP
diff --git a/png.5 b/png.5
index 08d60798c..7716e917d 100644
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "December 15, 2000"
+.TH PNG 5 "December 18, 2000"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
diff --git a/png.c b/png.c
index 9baf17b82..c04b1785a 100644
--- a/png.c
+++ b/png.c
@@ -1,7 +1,7 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * libpng version 1.0.9beta5 - December 15, 2000
+ * libpng version 1.0.9beta6 - December 18, 2000
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -13,14 +13,14 @@
 #include "png.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_0_9beta5 Your_png_h_is_not_version_1_0_9beta5;
+typedef version_1_0_9beta6 Your_png_h_is_not_version_1_0_9beta6;
 
 /* Version information for C files.  This had better match the version
  * string defined in png.h.  */
 
 #ifdef PNG_USE_GLOBAL_ARRAYS
 /* png_libpng_ver was changed to a function in version 1.0.5c */
-const char png_libpng_ver[18] = "1.0.9beta5";
+const char png_libpng_ver[18] = "1.0.9beta6";
 
 /* png_sig was changed to a function in version 1.0.5c */
 /* Place to hold the signature string for a PNG file. */
@@ -626,7 +626,7 @@ png_charp PNGAPI
 png_get_copyright(png_structp png_ptr)
 {
    if (png_ptr != NULL || png_ptr == NULL)  /* silence compiler warning */
-   return ((png_charp) "\n libpng version 1.0.9beta5 - December 15, 2000\n\
+   return ((png_charp) "\n libpng version 1.0.9beta6 - December 18, 2000\n\
    Copyright (c) 1998-2000 Glenn Randers-Pehrson\n\
    Copyright (c) 1996, 1997 Andreas Dilger\n\
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.\n");
@@ -644,8 +644,8 @@ png_get_libpng_ver(png_structp png_ptr)
 {
    /* Version of *.c files used when building libpng */
    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
-      return((png_charp) "1.0.9beta5");
-   return((png_charp) "1.0.9beta5");
+      return((png_charp) "1.0.9beta6");
+   return((png_charp) "1.0.9beta6");
 }
 
 png_charp PNGAPI
diff --git a/png.h b/png.h
index b5895286c..0949aee2d 100644
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.0.9beta5 - December 15, 2000
+ * libpng version 1.0.9beta6 - December 18, 2000
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -9,7 +9,7 @@
  * Authors and maintainers:
  *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *  libpng versions 0.97, January 1998, through 1.0.9beta5 - December 15, 2000: Glenn
+ *  libpng versions 0.97, January 1998, through 1.0.9beta6 - December 18, 2000: Glenn
  *  See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -58,7 +58,7 @@
  *    1.0.8beta1-4                  10008  2.1.0.8beta1-4
  *    1.0.8rc1                      10008  2.1.0.8rc1
  *    1.0.8                         10008  2.1.0.8
- *    1.0.9beta1-5                  10009  2.1.0.9beta1-5
+ *    1.0.9beta1-6                  10009  2.1.0.9beta1-6
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
@@ -85,7 +85,7 @@
  * If you modify libpng you may insert additional notices immediately following
  * this sentence.
  *
- * libpng versions 1.0.7, July 1, 2000, through  1.0.9beta5, December 15, 2000, are
+ * libpng versions 1.0.7, July 1, 2000, through  1.0.9beta6, December 18, 2000, are
  * Copyright (c) 2000 Glenn Randers-Pehrson, and are
  * distributed according to the same disclaimer and license as libpng-1.0.6
  * with the following individuals added to the list of Contributing Authors
@@ -190,13 +190,13 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    December 15, 2000
+ *    December 18, 2000
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
  *
  *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.0.9beta5 are Y2K compliant.  It is my belief that earlier
+ *    upward through 1.0.9beta6 are Y2K compliant.  It is my belief that earlier
  *    versions were also Y2K compliant.
  *
  *    Libpng only has three year fields.  One is a 2-byte unsigned integer
@@ -252,7 +252,7 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.0.9beta5"
+#define PNG_LIBPNG_VER_STRING "1.0.9beta6"
 
 #define PNG_LIBPNG_VER_SONUM   2
 
@@ -263,7 +263,7 @@
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero: */
 
-#define PNG_LIBPNG_VER_BUILD  5
+#define PNG_LIBPNG_VER_BUILD  6
 
 #define PNG_LIBPNG_BUILD_ALPHA    1
 #define PNG_LIBPNG_BUILD_BETA     2
@@ -920,9 +920,8 @@ typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp));
 
 /* Flags for MNG supported features */
 #define PNG_FLAG_MNG_EMPTY_PLTE     0x01
-#define PNG_MODE_EMBEDDED_IN_MNG    0x02
 #define PNG_FLAG_MNG_FILTER_64      0x04
-#define PNG_ALL_MNG_FEATURES        0x07
+#define PNG_ALL_MNG_FEATURES        0x05
 
 typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_size_t));
 typedef void (*png_free_ptr) PNGARG((png_structp, png_voidp));
@@ -1173,9 +1172,9 @@ struct png_struct_def
 };
 
 /* This prevents a compiler error in png_get_copyright() in png.c if png.c
-and png.h are both at * version 1.0.9beta5
+and png.h are both at * version 1.0.9beta6
  */
-typedef png_structp version_1_0_9beta5;
+typedef png_structp version_1_0_9beta6;
 
 typedef png_struct FAR * FAR * png_structpp;
 
@@ -2216,7 +2215,7 @@ extern PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp
 #endif
 
 #define PNG_HEADER_VERSION_STRING \
-   " libpng version 1.0.9beta5 - December 15, 2000 (header)\n"
+   " libpng version 1.0.9beta6 - December 18, 2000 (header)\n"
 
 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
 /* With these routines we avoid an integer divide, which will be slower on
@@ -2282,6 +2281,7 @@ extern PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp
 #define PNG_WROTE_tIME             0x200
 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
 #define PNG_BACKGROUND_IS_GRAY     0x800
+#define PNG_HAVE_PNG_SIGNATURE    0x1000
 
 /* flags for the transformations the PNG library does on the image data */
 #define PNG_BGR                0x0001
diff --git a/pngasmrd.h b/pngasmrd.h
index a0d501694..590359c8c 100644
--- a/pngasmrd.h
+++ b/pngasmrd.h
@@ -1,6 +1,6 @@
 /* pngasmrd.h - assembler version of utilities to read a PNG file
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1999, 2000 Glenn Randers-Pehrson
  *
diff --git a/pngconf.h b/pngconf.h
index b48c41a98..b881499fe 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,6 +1,6 @@
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -491,9 +491,12 @@
 #endif
 #endif
 
+/* Disable if you don't need to support PNGs that are embedded in MNG
+   datastreams */
 #ifndef PNG_NO_MNG_FEATURES
-#define PNG_MNG_FEATURES_SUPPORTED  /* Useful for MNG applications */
+#define PNG_MNG_FEATURES_SUPPORTED
 #endif
+
 /* Deprecated, will be removed */
 #ifndef PNG_NO_READ_EMPTY_PLTE
 #define PNG_READ_EMPTY_PLTE_SUPPORTED
diff --git a/pngerror.c b/pngerror.c
index 00668fbd8..327ce3c70 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,7 +1,7 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pnggccrd.c b/pnggccrd.c
index 9b8eecc3d..cc55dc8ed 100644
--- a/pnggccrd.c
+++ b/pnggccrd.c
@@ -6,7 +6,7 @@
  *     and http://www.intel.com/drg/pentiumII/appnotes/923/923.htm
  *     for Intel's performance analysis of the MMX vs. non-MMX code.
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * Copyright (c) 1998, Intel Corporation
diff --git a/pngget.c b/pngget.c
index edfc8eaed..876c63d0b 100644
--- a/pngget.c
+++ b/pngget.c
@@ -1,7 +1,7 @@
 
 /* pngget.c - retrieval of values from info struct
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngmem.c b/pngmem.c
index 336c4f3e1..7252ffafd 100644
--- a/pngmem.c
+++ b/pngmem.c
@@ -1,7 +1,7 @@
 
 /* pngmem.c - stub functions for memory allocation
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngpread.c b/pngpread.c
index 5766b37fa..765964199 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngread.c b/pngread.c
index b2ced9b92..ecc736b82 100644
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@
 
 /* pngread.c - read a PNG file
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -246,6 +246,8 @@ png_read_info(png_structp png_ptr, png_infop info_ptr)
          else
             png_error(png_ptr, "PNG file corrupted by ASCII conversion");
       }
+      if (num_checked < 3)
+         png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
    }
 
    for(;;)
@@ -710,7 +712,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
  * not called png_set_interlace_handling(), the display_row buffer will
  * be ignored, so pass NULL to it.
  *
- * [*] png_handle_alpha() does not exist yet, as of libpng version 1.0.9beta5
+ * [*] png_handle_alpha() does not exist yet, as of libpng version 1.0.9beta6
  */
 
 void PNGAPI
@@ -759,7 +761,7 @@ png_read_rows(png_structp png_ptr, png_bytepp row,
  * only call this function once.  If you desire to have an image for
  * each pass of a interlaced image, use png_read_rows() instead.
  *
- * [*] png_handle_alpha() does not exist yet, as of libpng version 1.0.9beta5
+ * [*] png_handle_alpha() does not exist yet, as of libpng version 1.0.9beta6
  */
 void PNGAPI
 png_read_image(png_structp png_ptr, png_bytepp image)
diff --git a/pngrio.c b/pngrio.c
index c70282758..732171488 100644
--- a/pngrio.c
+++ b/pngrio.c
@@ -1,7 +1,7 @@
 
 /* pngrio.c - functions for data input
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngrtran.c b/pngrtran.c
index 9064b4833..04320db25 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,7 +1,7 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngrutil.c b/pngrutil.c
index 715c20df6..7d5b14b22 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,7 +1,7 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -353,15 +353,31 @@ png_handle_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    if (compression_type != PNG_COMPRESSION_TYPE_BASE)
       png_error(png_ptr, "Unknown compression method in IHDR");
 
-   if(
 #if defined(PNG_MNG_FEATURES_SUPPORTED)
-      !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+   /* Accept filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not read a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&png_ptr->mng_features_permitted)
+      png_warning(png_ptr,"MNG features are not allowed in a PNG datastream\n");
+   if(!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
       (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
+      ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
       (color_type == PNG_COLOR_TYPE_RGB || 
        color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
-#endif
-      filter_type != PNG_FILTER_TYPE_BASE)
+       filter_type != PNG_FILTER_TYPE_BASE)
       png_error(png_ptr, "Unknown filter method in IHDR");
+   if(filter_type != PNG_FILTER_TYPE_BASE)
+      png_warning(png_ptr, "Invalid filter method in IHDR");
+#else
+   if(filter_type != PNG_FILTER_TYPE_BASE)
+      png_error(png_ptr, "Unknown filter method in IHDR");
+#endif
 
    /* set internal variables */
    png_ptr->width = width;
diff --git a/pngset.c b/pngset.c
index b8b0589c6..05b2908f4 100644
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngtest.c b/pngtest.c
index af54813eb..c8d1f405b 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,7 +1,7 @@
 
 /* pngtest.c - a simple test program to test libpng
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -1449,4 +1449,4 @@ main(int argc, char *argv[])
 }
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_0_9beta5 your_png_h_is_not_version_1_0_9beta5;
+typedef version_1_0_9beta6 your_png_h_is_not_version_1_0_9beta6;
diff --git a/pngtrans.c b/pngtrans.c
index 3e40074aa..c5c7fc38b 100644
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,7 +1,7 @@
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngvcrd.c b/pngvcrd.c
index fdc3d3f93..2daa4fe15 100644
--- a/pngvcrd.c
+++ b/pngvcrd.c
@@ -2,7 +2,7 @@
  *
  * For Intel x86 CPU and Microsoft Visual C++ compiler
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * Copyright (c) 1998, Intel Corporation
diff --git a/pngwio.c b/pngwio.c
index 8baacea86..18b49ff8a 100644
--- a/pngwio.c
+++ b/pngwio.c
@@ -1,7 +1,7 @@
 
 /* pngwio.c - functions for data output
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngwrite.c b/pngwrite.c
index f1f1d3a26..b004a066d 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@
 
 /* pngwrite.c - general routines to write a PNG file
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -28,6 +28,13 @@ png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
    if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
    {
    png_write_sig(png_ptr); /* write PNG signature */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted))
+   {
+      png_warning(png_ptr,"MNG features are not allowed in a PNG datastream\n");
+      png_ptr->mng_features_permitted=0;
+   }
+#endif
    /* write IHDR information. */
    png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
       info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
@@ -774,6 +781,15 @@ png_write_row(png_structp png_ptr, png_bytep row)
       png_do_write_transformations(png_ptr);
 
 #if defined(PNG_MNG_FEATURES_SUPPORTED)
+   /* Write filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not write a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
    if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
    {
@@ -977,6 +993,11 @@ void PNGAPI
 png_set_filter(png_structp png_ptr, int method, int filters)
 {
    png_debug(1, "in png_set_filter\n");
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+      if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+      (method == PNG_INTRAPIXEL_DIFFERENCING))
+         method = PNG_FILTER_TYPE_BASE;
+#endif
    if (method == PNG_FILTER_TYPE_BASE)
    {
       switch (filters & (PNG_ALL_FILTERS | 0x07))
diff --git a/pngwtran.c b/pngwtran.c
index 5dd7007e9..b33f5e986 100644
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,7 +1,7 @@
 
 /* pngwtran.c - transforms the data in a row for PNG writers
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngwutil.c b/pngwutil.c
index 4d669da71..53039a598 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@
 
 /* pngwutil.c - utilities to write a PNG file
  *
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -131,6 +131,8 @@ png_write_sig(png_structp png_ptr)
    /* write the rest of the 8 byte signature */
    png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
       (png_size_t)8 - png_ptr->sig_bytes);
+   if(png_ptr->sig_bytes < 3)
+      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
 }
 
 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
@@ -419,9 +421,21 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
       compression_type = PNG_COMPRESSION_TYPE_BASE;
    }
 
+   /* Write filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not write a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
    if (
 #if defined(PNG_MNG_FEATURES_SUPPORTED)
       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+      ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+      (color_type == PNG_COLOR_TYPE_RGB || 
+       color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
       (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
 #endif
       filter_type != PNG_FILTER_TYPE_BASE)
diff --git a/projects/msvc/README.txt b/projects/msvc/README.txt
index debd2dd66..e2ec45cb7 100644
--- a/projects/msvc/README.txt
+++ b/projects/msvc/README.txt
@@ -1,5 +1,5 @@
 Microsoft Developer Studio Build File, Format Version 6.00 for
-libpng 1.0.9beta5 (December 15, 2000) and zlib
+libpng 1.0.9beta6 (December 18, 2000) and zlib
 
 Copyright (C) 2000 Simon-Pierre Cadieux
 For conditions of distribution and use, see copyright notice in png.h
diff --git a/projects/msvc/png32ms.def b/projects/msvc/png32ms.def
index cc8533285..919be03cb 100644
--- a/projects/msvc/png32ms.def
+++ b/projects/msvc/png32ms.def
@@ -6,7 +6,7 @@ LIBRARY
 DESCRIPTION "PNG image compression library for Windows"
 
 EXPORTS
-;Version 1.0.9beta5
+;Version 1.0.9beta6
   png_build_grayscale_palette  @1
   png_check_sig        @2
   png_chunk_error      @3
diff --git a/projects/wince/READMEE.WCE b/projects/wince/READMEE.WCE
index 5af7b646f..a2946d0e5 100644
--- a/projects/wince/READMEE.WCE
+++ b/projects/wince/READMEE.WCE
@@ -8,9 +8,9 @@ libpng for WindowsCE Rel.1.0
 
 Introduction
 ============
-This is libpng 1.0.9beta5 ported to WindowsCE 2.0 and 2.11.
-libpng 1.0.9beta5 is a PNG reference library.
-See README, a document of original libpng 1.0.9beta5.
+This is libpng 1.0.9beta6 ported to WindowsCE 2.0 and 2.11.
+libpng 1.0.9beta6 is a PNG reference library.
+See README, a document of original libpng 1.0.9beta6.
 
 zlib for WindowsCE
 ==================
@@ -23,7 +23,7 @@ This software is provided 'as-is', without any express or implied
 warranty.  In no event will the authors be held liable for any damages
 arising from the use of this software.
 
-See README and LICENSE, documents of original libpng 1.0.9beta5, for conditions
+See README and LICENSE, documents of original libpng 1.0.9beta6, for conditions
 of use and distribution.
 
 Files
diff --git a/projects/wince/READMEJ.WCE b/projects/wince/READMEJ.WCE
index 87e10e03b..e752286b4 100644
--- a/projects/wince/READMEJ.WCE
+++ b/projects/wince/READMEJ.WCE
@@ -24,7 +24,7 @@ libpng
 になったいかなる被害についても、作者、配布者、その他利用者以外の人物、
 団体に責任をとる義務はないものとします。
 
-その他、このソフトウェアの利用条件については、原版である libpng 1.0.9beta5に
+その他、このソフトウェアの利用条件については、原版である libpng 1.0.9beta6に
 準拠するものとします。詳しくは、付属の README,LICENSE をお読みください。
 
 収録内容
diff --git a/projects/wince/png32ce.def b/projects/wince/png32ce.def
index 2793799db..abba51a75 100644
--- a/projects/wince/png32ce.def
+++ b/projects/wince/png32ce.def
@@ -5,7 +5,7 @@
 LIBRARY lpngce
 
 EXPORTS
-;Version 1.0.9beta5
+;Version 1.0.9beta6
   png_build_grayscale_palette  @1
   png_check_sig        @2
   png_chunk_error      @3
diff --git a/scripts/makefile.aix b/scripts/makefile.aix
index 5ca4286e0..3456f4518 100644
--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -18,7 +18,7 @@ RM = rm -f
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 prefix=/usr/local
diff --git a/scripts/makefile.beos b/scripts/makefile.beos
index 928eb3a3b..80762f4f2 100644
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -31,7 +31,7 @@ RANLIB=ranlib
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # where make install puts libpng.a, libpng.so*, and png.h
diff --git a/scripts/makefile.cygwin b/scripts/makefile.cygwin
index f39a11fb1..ccf959105 100644
--- a/scripts/makefile.cygwin
+++ b/scripts/makefile.cygwin
@@ -38,7 +38,7 @@ CFLAGS=-I$(ZLIBINC) -Wall -O3 $(ALIGN) -funroll-loops \
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=cygpng$(PNGMAJ).dll
diff --git a/scripts/makefile.dec b/scripts/makefile.dec
index 41e118ee8..c754d657d 100644
--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -17,7 +17,7 @@ ZLIBINC=../zlib
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 CC=cc
diff --git a/scripts/makefile.gcmmx b/scripts/makefile.gcmmx
index 6983cd1d8..9445d9b6e 100644
--- a/scripts/makefile.gcmmx
+++ b/scripts/makefile.gcmmx
@@ -37,7 +37,7 @@ RANLIB=ranlib
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 INCPATH=$(prefix)/include
diff --git a/scripts/makefile.hpux b/scripts/makefile.hpux
index 3445bc49f..12c5cbe31 100644
--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -18,7 +18,7 @@ RANLIB=ranlib
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # where make install puts libpng.a and png.h
diff --git a/scripts/makefile.linux b/scripts/makefile.linux
index 8e524a148..c86fea8d0 100644
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -34,7 +34,7 @@ RANLIB=ranlib
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 INCPATH=$(prefix)/include
diff --git a/scripts/makefile.sco b/scripts/makefile.sco
index 15bfa36ea..5d7b4b533 100644
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -25,7 +25,7 @@ RANLIB=echo
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 INCPATH=$(prefix)/include
diff --git a/scripts/makefile.sggcc b/scripts/makefile.sggcc
index 08e4cb791..cd6526752 100644
--- a/scripts/makefile.sggcc
+++ b/scripts/makefile.sggcc
@@ -19,8 +19,8 @@ CFLAGS=-I$(ZLIBINC) -O2 $(WARNMORE) -fPIC -mabi=n32 # -g -DPNG_DEBUG=5
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
 LDSHARED=gcc -shared
 
-VER=1.0.9beta5
-LIBS=libpng.so.1.0.9beta5
+VER=1.0.9beta6
+LIBS=libpng.so.1.0.9beta6
 SHAREDLIB=libpng.so
 libdir=$(prefix)/lib32
 
diff --git a/scripts/makefile.solaris b/scripts/makefile.solaris
index c00472f72..1273f6552 100644
--- a/scripts/makefile.solaris
+++ b/scripts/makefile.solaris
@@ -31,7 +31,7 @@ RANLIB=echo
 # read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
 # have to change it.
 PNGMAJ = 2
-PNGMIN = 1.0.9beta5
+PNGMIN = 1.0.9beta6
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 INCPATH=$(prefix)/include
diff --git a/scripts/pngdef.pas b/scripts/pngdef.pas
index 707f96b06..4e88d34ed 100644
--- a/scripts/pngdef.pas
+++ b/scripts/pngdef.pas
@@ -5,7 +5,7 @@ unit pngdef;
 interface
 
 const
-  PNG_LIBPNG_VER_STRING = '1.0.9beta5';
+  PNG_LIBPNG_VER_STRING = '1.0.9beta6';
   PNG_LIBPNG_VER        =  10009;
 
 type