diff --git a/ANNOUNCE b/ANNOUNCE
index fdb90c069..06381d725 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -59,6 +59,8 @@ Version 1.6.18beta05 [May 31, 2015]
     sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
   Changed png_voidcast(), etc., to voidcast(), etc., in contrib/tools/pngfix.c
     to avoid confusion with the libpng private macros.
+  Fixed old cut&paste bug in the weighted filter selection code in
+    pngwutil.c, introduced in libpng-0.95, March 1997.
 
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diff --git a/CHANGES b/CHANGES
index 14cdf1661..84e311e9a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -5244,6 +5244,8 @@ Version 1.6.18beta05 [May 31, 2015]
     sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
   Changed png_voidcast(), etc., to voidcast(), etc., in contrib/tools/pngfix.c
     to avoid confusion with the libpng private macros.
+  Fixed old cut&paste bug in the weighted filter selection code in
+    pngwutil.c, introduced in libpng-0.95, March 1997.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/pngwutil.c b/pngwutil.c
index d83e37f51..66e5fcfdd 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@
 
 /* pngwutil.c - utilities to write a PNG file
  *
- * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Last changed in libpng 1.6.18 [(PENDING RELEASE)]
  * Copyright (c) 1998-2015 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.)
@@ -2814,7 +2814,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
 
          for (j = 0; j < num_p_filters; j++)
          {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
             {
                sumlo = (sumlo * png_ptr->filter_weights[j]) >>
                    PNG_WEIGHT_SHIFT;