diff -ru4NwbB libpng-1.5.0/png.h libpng-1.5.1beta02/png.h
--- libpng-1.5.0/png.h	2011-01-06 07:02:36.101650980 -0600
+++ libpng-1.5.1beta02/png.h	2011-01-14 17:13:54.158784105 -0600
@@ -143,8 +143,9 @@
  *    1.4.4                   14    10404  14.so.14.4[.0]
  *    1.5.0beta01-58          15    10500  15.so.15.0[.0]
  *    1.5.0rc01-07            15    10500  15.so.15.0[.0]
  *    1.5.0                   15    10500  15.so.15.0[.0]
+ *    1.5.1beta01-02          15    10501  15.so.15.1[.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-1.5.0/pngread.c libpng-1.5.1beta02/pngread.c
--- libpng-1.5.0/pngread.c	2011-01-06 07:02:36.187926550 -0600
+++ libpng-1.5.1beta02/pngread.c	2011-01-14 17:13:54.242979524 -0600
@@ -1,8 +1,8 @@
 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.5.0 [January 6, 2011]
+ * Last changed in libpng 1.5.1 [$RDATE%]
  * Copyright (c) 1998-2011 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.)
  *
@@ -840,9 +840,9 @@
       png_start_read_image(png_ptr);
    }
    else
    {
-      if (!(png_ptr->transformations & PNG_INTERLACE))
+      if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
       {
          /* Caller called png_start_read_image or png_read_update_info without
           * first turning on the PNG_INTERLACE transform.  We can fix this here,
           * but the caller should do it!
diff -ru4NwbB libpng-1.5.0/pngrtran.c libpng-1.5.1beta02/pngrtran.c
--- libpng-1.5.0/pngrtran.c	2011-01-06 07:02:36.208212217 -0600
+++ libpng-1.5.1beta02/pngrtran.c	2011-01-14 17:13:54.262679289 -0600
@@ -1,8 +1,8 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * Last changed in libpng 1.5.0 [January 6, 2011]
+ * Last changed in libpng 1.5.1 [(PENDING RELEASE)]
  * Copyright (c) 1998-2011 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.)
  *
@@ -2426,9 +2426,9 @@
    int rgb_error = 0;
 
    png_debug(1, "in png_do_rgb_to_gray");
 
-   if (
+   if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) &&
        (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
       png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
@@ -3777,9 +3777,9 @@
          row_info->pixel_depth = 8;
          row_info->rowbytes = row_width;
       }
 
-      else if (row_info->bit_depth == 8)
+      if (row_info->bit_depth == 8)
       {
          {
             if (trans_alpha != NULL)
             {
diff -ru4NwbB libpng-1.5.0/pngrutil.c libpng-1.5.1beta02/pngrutil.c
--- libpng-1.5.0/pngrutil.c	2011-01-06 07:02:36.222125010 -0600
+++ libpng-1.5.1beta02/pngrutil.c	2011-01-14 17:13:54.276134000 -0600
@@ -1247,9 +1247,11 @@
          char umsg[80];
 
          png_snprintf2(umsg, 80,
              "Ignoring iCCP chunk with declared size = %u "
-              "and actual length = %u", profile_size, profile_length);
+              "and actual length = %u",
+              (unsigned int) profile_size,
+              (unsigned int) profile_length);
          png_warning(png_ptr, umsg);
       }
 #else
       png_warning(png_ptr,