diff --git modules/image/image.admin.inc modules/image/image.admin.inc
index d72fdf4..8d785d6 100644
--- modules/image/image.admin.inc
+++ modules/image/image.admin.inc
@@ -773,8 +773,14 @@ function theme_image_style_preview($variables) {
 
   // Set up preview file information.
   $preview_file = image_style_path($style['name'], $original_path);
-  if (!file_exists($preview_file)) {
-    image_style_create_derivative($style, $original_path, $preview_file);
+
+  if (!(file_exists($preview_file) ||
+        image_style_create_derivative($style, $original_path, $preview_file))) {
+    drupal_set_message(t('Preview image could not be created. ' .
+                         'Check permissions on your %d directory.',
+                         array('%d' => drupal_dirname($preview_file))),
+                       'warning', FALSE);
+    return '';
   }
   $preview_image = image_get_info($preview_file);
   if ($preview_image['width'] > $preview_image['height']) {