diff --git a/modules/image/image.module b/modules/image/image.module
index b3ba7c4..e47d174 100644
--- a/modules/image/image.module
+++ b/modules/image/image.module
@@ -1025,8 +1025,10 @@ function image_style_url($style_name, $path) {
   }

   $file_url = file_create_url($uri);
-  // Append the query string with the token.
-  return $file_url . (strpos($file_url, '?') !== FALSE ? '&' : '?') . drupal_http_build_query($token_query);
+  $file_url = $file_url . (strpos($file_url, '?') !== FALSE ? '&' : '?') . drupal_http_build_query($token_query);
+  drupal_alter('image_style_url', $file_url);
+
+  return $file_url;
 }

 /**