diff --git a/ANNOUNCE b/ANNOUNCE
index 904f34f96..1592911c0 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.6.3beta03 - April 27, 2013
+Libpng 1.6.3beta03 - April 29, 2013
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -35,9 +35,11 @@ Version 1.6.3beta02 [April 26, 2013]
   Test for 'arm*' not just 'arm' in the host_cpu configure variable.
   Rebuilt the configure scripts.
 
-Version 1.6.3beta03 [April 27, 2013]
+Version 1.6.3beta03 [April 29, 2013]
   Expanded manual paragraph about writing private chunks, particularly
     the need to call png_set_keep_unknown_chunks() when writing them.
+  Avoid dereferencing NULL pointer possibly returned from
+     png_create_write_struct() (Andrew Church).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 71ccd7637..07f68c393 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4517,9 +4517,11 @@ Version 1.6.3beta02 [April 26, 2013]
   Test for 'arm*' not just 'arm' in the host_cpu configure variable.
   Rebuilt the configure scripts.
 
-Version 1.6.3beta03 [April 27, 2013]
+Version 1.6.3beta03 [April 29, 2013]
   Expanded manual paragraph about writing private chunks, particularly
     the need to call png_set_keep_unknown_chunks() when writing them.
+  Avoid dereferencing NULL pointer possibly returned from
+     png_create_write_struct() (Andrew Church).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/pngwrite.c b/pngwrite.c
index 33924aac0..b71a3d345 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -494,51 +494,50 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
    png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
 #endif /* PNG_USER_MEM_SUPPORTED */
+   if (png_ptr != NULL)
+   {
+      /* Set the zlib control values to defaults; they can be overridden by the
+       * application after the struct has been created.
+       */
+      png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
 
-   /* Set the zlib control values to defaults; they can be overridden by the
-    * application after the struct has been created.
-    */
-   png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
-
-   /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
-    * pngwutil.c defaults it according to whether or not filters will be used,
-    * and ignores this setting.
-    */
-   png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
-   png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
-   png_ptr->zlib_mem_level = 8;
-   png_ptr->zlib_window_bits = 15;
-   png_ptr->zlib_method = 8;
+      /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
+       * pngwutil.c defaults it according to whether or not filters will be
+       * used, and ignores this setting.
+       */
+      png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
+      png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
+      png_ptr->zlib_mem_level = 8;
+      png_ptr->zlib_window_bits = 15;
+      png_ptr->zlib_method = 8;
 
 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-   png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
-   png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
-   png_ptr->zlib_text_mem_level = 8;
-   png_ptr->zlib_text_window_bits = 15;
-   png_ptr->zlib_text_method = 8;
+      png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
+      png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
+      png_ptr->zlib_text_mem_level = 8;
+      png_ptr->zlib_text_window_bits = 15;
+      png_ptr->zlib_text_method = 8;
 #endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
 
-   /* This is a highly dubious configuration option; by default it is off, but
-    * it may be appropriate for private builds that are testing extensions not
-    * conformant to the current specification, or of applications that must not
-    * fail to write at all costs!
-    */
-#  ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
+      /* This is a highly dubious configuration option; by default it is off,
+       * but it may be appropriate for private builds that are testing
+       * extensions not conformant to the current specification, or of
+       * applications that must not fail to write at all costs!
+       */
+#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
       png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
       /* In stable builds only warn if an application error can be completely
        * handled.
        */
-#  endif
+#endif
 
-   /* App warnings are warnings in release (or release candidate) builds but
-    * are errors during development.
-    */
-#  if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+      /* App warnings are warnings in release (or release candidate) builds but
+       * are errors during development.
+       */
+#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
       png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
-#  endif
+#endif
 
-   if (png_ptr != NULL)
-   {
       /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
        * do it itself) avoiding setting the default function if it is not
        * required.