--- /responsive_images/responsive_images.module	2011-08-27 17:12:48.000000000 +0200
+++ /responsive_images/responsive_images.module	2012-03-13 16:08:09.000000000 +0100
@@ -291,3 +291,17 @@
 
   return '<img' . drupal_attributes($attributes) . ' />';
 }
\ Kein Zeilenumbruch am Dateiende.
+
+/**
+ * Theme preprocess function for theme_field() and field.tpl.php.
+ *
+ * Add a additional CSS class to help to identify responsive images output.
+ *
+ * @see theme_field()
+ * @see template_process_field()
+ */
+function responsive_images_process_field(&$variables, $hook) {
+  if ($variables['element']['#formatter'] == 'responsive_image') {
+    $variables['classes'] .= ' responsive-image-items';
+  }
+}