diff -ru4NwbB libpng-1.2.44/Makefile.am libpng-1.2.45beta02/Makefile.am
--- libpng-1.2.44/Makefile.am	2010-06-25 19:31:28.410414574 -0500
+++ libpng-1.2.45beta02/Makefile.am	2011-06-07 15:54:20.443124385 -0500
@@ -101,9 +101,10 @@
 	cp libpng-config $@
 
 libpng.sym: png.h pngconf.h
 	rm -f $@ $@.new
-	$(CPP) @LIBPNG_DEFINES@ $(CPPFLAGS) -DPNG_BUILDSYMS $(srcdir)/png.h | \
+	$(CPP) @LIBPNG_DEFINES@ $(CPPFLAGS) -DPNG_BUILDSYMS $(srcdir)/png.h $(srcdir)/$@
+	cat $(srcdir)/$@ | \
 		$(SED) -n -e \
 		's|^.*PNG_FUNCTION_EXPORT[ 	]*\([$(AN)]*\).*$$|$(SYMBOL_PREFIX)\1|p' \
 		-e 's|^.*PNG_DATA_EXPORT[ 	]*\([$(AN)]*\).*$$|$(SYMBOL_PREFIX)\1|p' \
 			>$@.new
diff -ru4NwbB libpng-1.2.44/png.h libpng-1.2.45beta02/png.h
--- libpng-1.2.44/png.h	2010-06-25 19:31:14.374271550 -0500
+++ libpng-1.2.45beta02/png.h	2011-06-07 15:54:06.550703092 -0500
@@ -230,9 +230,9 @@
  *    1.2.36                  13    10236  12.so.0.36[.0]
  *    1.2.37beta01-03         13    10237  12.so.0.37[.0]
  *    1.2.37rc01              13    10237  12.so.0.37[.0]
  *    1.2.37                  13    10237  12.so.0.37[.0]
- *    1.2.45                  10    10045  12.so.0.45[.0]
+ *    1.0.45                  10    10045  12.so.0.45[.0]
  *    1.0.46                  10    10046  10.so.0.46[.0]
  *    1.2.38beta01            13    10238  12.so.0.38[.0]
  *    1.2.38rc01-03           13    10238  12.so.0.38[.0]
  *    1.0.47                  10    10047  10.so.0.47[.0]
@@ -261,8 +261,9 @@
  *    1.2.43                  13    10243  12.so.0.43[.0]
  *    1.2.44beta01-03         13    10244  12.so.0.44[.0]
  *    1.2.44rc01-03           13    10244  12.so.0.44[.0]
  *    1.2.44                  13    10244  12.so.0.44[.0]
+ *    1.2.45beta01-02         13    10245  12.so.0.45[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
  *    used for changes in backward compatibility, as it is intended.  The
diff -ru4NwbB libpng-1.2.44/pngerror.c libpng-1.2.45beta02/pngerror.c
--- libpng-1.2.44/pngerror.c	2010-06-25 19:31:14.405023751 -0500
+++ libpng-1.2.45beta02/pngerror.c	2011-06-07 15:54:06.580066211 -0500
@@ -86,14 +86,19 @@
 #else
 void PNGAPI
 png_err(png_structp png_ptr)
 {
+   /* Prior to 1.2.45 the error_fn received a NULL pointer, expressed
+    * erroneously as '\0', instead of the empty string "".  This was
+    * apparently an error, introduced in libpng-1.2.20, and png_default_error
+    * will crash in this case.
+    */
    if (png_ptr != NULL && png_ptr->error_fn != NULL)
-      (*(png_ptr->error_fn))(png_ptr, '\0');
+      (*(png_ptr->error_fn))(png_ptr, "");
 
    /* If the custom handler doesn't exist, or if it returns,
       use the default handler, which will not return. */
-   png_default_error(png_ptr, '\0');
+   png_default_error(png_ptr, "");
 }
 #endif /* PNG_ERROR_TEXT_SUPPORTED */
 
 #ifdef PNG_WARNINGS_SUPPORTED
@@ -180,10 +185,15 @@
    else
    {
       buffer[iout++] = ':';
       buffer[iout++] = ' ';
-      png_memcpy(buffer + iout, error_message, PNG_MAX_ERROR_TEXT);
-      buffer[iout + PNG_MAX_ERROR_TEXT - 1] = '\0';
+
+      iin = 0;
+      while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
+         buffer[iout++] = error_message[iin++];
+
+      /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
+      buffer[iout] = '\0';
    }
 }
 
 #ifdef PNG_READ_SUPPORTED
diff -ru4NwbB libpng-1.2.44/pngmem.c libpng-1.2.45beta02/pngmem.c
--- libpng-1.2.44/pngmem.c	2010-06-25 19:31:14.423245005 -0500
+++ libpng-1.2.45beta02/pngmem.c	2011-06-07 15:54:06.597287397 -0500
@@ -441,9 +441,9 @@
  * need to allocate exactly 64K, so whatever you call here must
  * have the ability to do that.
  */
 
-png_voidp PNGAPI
+png_voidp /* PRIVATE */
 png_calloc(png_structp png_ptr, png_uint_32 size)
 {
    png_voidp ret;
 
diff -ru4NwbB libpng-1.2.44/pngrtran.c libpng-1.2.45beta02/pngrtran.c
--- libpng-1.2.44/pngrtran.c	2010-06-25 19:31:14.461091362 -0500
+++ libpng-1.2.45beta02/pngrtran.c	2011-06-07 15:54:06.634204288 -0500
@@ -675,12 +675,23 @@
 void PNGAPI
 png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
    double green)
 {
-   int red_fixed = (int)((float)red*100000.0 + 0.5);
-   int green_fixed = (int)((float)green*100000.0 + 0.5);
+   int red_fixed, green_fixed;
    if (png_ptr == NULL)
       return;
+   if (red > 21474.83647 || red < -21474.83648 ||
+       green > 21474.83647 || green < -21474.83648)
+   {
+      png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
+      red_fixed = -1;
+      green_fixed = -1;
+   }
+   else
+   {
+      red_fixed = (int)((float)red*100000.0 + 0.5);
+      green_fixed = (int)((float)green*100000.0 + 0.5);
+   }
    png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
 }
 #endif
 
@@ -1195,10 +1206,9 @@
    if (png_ptr->transformations & PNG_EXPAND)
    {
       if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
-         if (png_ptr->num_trans &&
-              (png_ptr->transformations & PNG_EXPAND_tRNS))
+         if (png_ptr->num_trans)
             info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
          else
             info_ptr->color_type = PNG_COLOR_TYPE_RGB;
          info_ptr->bit_depth = 8;
diff -ru4NwbB libpng-1.2.44/pngwrite.c libpng-1.2.45beta02/pngwrite.c
--- libpng-1.2.44/pngwrite.c	2010-06-25 19:31:14.515866839 -0500
+++ libpng-1.2.45beta02/pngwrite.c	2011-06-07 15:54:06.687631400 -0500
@@ -294,8 +294,9 @@
          int keep = png_handle_as_unknown(png_ptr, up->name);
          if (keep != PNG_HANDLE_CHUNK_NEVER &&
             up->location && (up->location & PNG_HAVE_PLTE) &&
             !(up->location & PNG_HAVE_IDAT) &&
+            !(up->location & PNG_AFTER_IDAT) &&
             ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
             (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
          {
             png_write_chunk(png_ptr, up->name, up->data, up->size);
diff -ru4NwbB libpng-1.2.44/projects/xcode/libpng.xcodeproj/project.pbxproj libpng-1.2.45beta02/projects/xcode/libpng.xcodeproj/project.pbxproj
--- libpng-1.2.44/projects/xcode/libpng.xcodeproj/project.pbxproj	2010-06-25 19:31:15.672252821 -0500
+++ libpng-1.2.45beta02/projects/xcode/libpng.xcodeproj/project.pbxproj	2011-06-07 15:54:07.827815069 -0500
@@ -221,9 +221,9 @@
 			buildSettings = {
 				COPY_PHASE_STRIP = NO;
 				DYLIB_COMPATIBILITY_VERSION = 3;
 				DYLIB_CURRENT_VERSION = 3;
-				FRAMEWORK_VERSION = 1.2.44;
+				FRAMEWORK_VERSION = 1.2.45beta02;
 				GCC_PRECOMPILE_PREFIX_HEADER = NO;
 				GCC_PREFIX_HEADER = "";
 				INFOPLIST_FILE = Info.plist;
 				INSTALL_PATH = "@executable_path/../Frameworks";
@@ -239,9 +239,9 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				DYLIB_COMPATIBILITY_VERSION = 3;
 				DYLIB_CURRENT_VERSION = 3;
-				FRAMEWORK_VERSION = 1.2.44;
+				FRAMEWORK_VERSION = 1.2.45beta02;
 				GCC_PRECOMPILE_PREFIX_HEADER = NO;
 				GCC_PREFIX_HEADER = "";
 				INFOPLIST_FILE = Info.plist;
 				INSTALL_PATH = "@executable_path/../Frameworks";