diff --git a/core/includes/common.inc b/core/includes/common.inc
index 1c301f4..c32ba19 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -3031,7 +3031,7 @@ function drupal_render_page($page) {
  *     @code
  *     array(
  *       '#theme' => 'image',
- *       '#attributes' => array('class' => 'foo'),
+ *       '#attributes' => array('class' => array('foo')),
  *       '#theme_wrappers' => array('container'),
  *     );
  *     @endcode
@@ -3040,7 +3040,7 @@ function drupal_render_page($page) {
  *     @code
  *     array(
  *       '#theme' => 'image',
- *       '#attributes' => array('class' => 'foo'),
+ *       '#attributes' => array('class' => array('foo')),
  *       '#theme_wrappers' => array(
  *         'container' => array(
  *           '#attributes' => array('class' => 'bar'),