--- src/png_reader.cpp.orig	2011-09-25 20:12:10.000000000 -0700
+++ src/png_reader.cpp	2011-09-25 20:17:17.000000000 -0700
@@ -82,7 +82,7 @@
     {
         png_size_t check;
         check = (png_size_t)fread(data, (png_size_t)1, length,
-                                  (FILE *)png_ptr->io_ptr);
+                                  (FILE *)png_get_io_ptr(png_ptr));
 
         if (check != length)
         {