--- pngwutil.c.orig	2006-11-28 17:25:59.000000000 +0100
+++ pngwutil.c	2006-12-27 15:47:53.000000000 +0100
@@ -733,7 +733,7 @@ png_write_iCCP(png_structp png_ptr, png_
    png_size_t name_len;
    png_charp new_name;
    compression_state comp;
-   int embedded_profile_len = 0;
+   unsigned int embedded_profile_len = 0;
 
    png_debug(1, "in png_write_iCCP\n");
 
@@ -757,8 +757,8 @@ png_write_iCCP(png_structp png_ptr, png_
       profile_len = 0;
 
    if (profile_len > 3)
-      embedded_profile_len = ((*(profile  ))<<24) | ((*(profile+1))<<16) |
-          ((*(profile+2))<< 8) | ((*(profile+3))    );
+      embedded_profile_len = (((png_byte)(*(profile)))<<24) | (((png_byte)(*(profile+1)))<<16) |
+          (((png_byte)(*(profile+2)))<< 8) | ((png_byte)(*(profile+3)));
 
    if (profile_len < embedded_profile_len)
      {