diff -urN optipng-0.5.4.orig/src/opngreduc.c optipng-0.5.4/src/opngreduc.c
--- optipng-0.5.4.orig/src/opngreduc.c	2006-11-28 01:55:45.000000000 -0200
+++ optipng-0.5.4/src/opngreduc.c	2006-11-28 01:56:54.000000000 -0200
@@ -80,10 +80,6 @@
    if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
       if (sig_bit != &info_ptr->sig_bit)
          goto error;
-   if (png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, &trans_values))
-      if (trans != info_ptr->trans || num_trans != info_ptr->num_trans ||
-          trans_values != &info_ptr->trans_values)
-         goto error;
 
    /* Also check png_ptr.  (It's not much, but we're doing what we can.) */
    if (png_get_compression_buffer_size(png_ptr) != png_ptr->zbuf_size)