diff -u b/modules/system/image.gd.inc b/modules/system/image.gd.inc
--- b/modules/system/image.gd.inc
+++ b/modules/system/image.gd.inc
@@ -304,14 +304,14 @@
     if ($transparent >= 0) {
       // Find out the number of colors in the image palette. It will be 0 for
       // truecolor images.
-      $palette_size = imagecolorstotal($image->getResource());
+      $palette_size = imagecolorstotal($image->resource);
       if ($palette_size == 0 || $transparent < $palette_size) {
         // Set the transparent color in the new resource, either if it is a
         // truecolor image or if the transparent color is part of the palette.
         // Since the index of the transparency color is a property of the
         // image rather than of the palette, it is possible that an image
         // could be created with this index set outside the palette size.
-        $transparent_color = imagecolorsforindex($image->getResource(), $transparent);
+        $transparent_color = imagecolorsforindex($image->resource, $transparent);
         $transparent = imagecolorallocate($res, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);
 
         // Flood with our new transparent color.