diff --git a/src/wp-admin/includes/ms.php b/src/wp-admin/includes/ms.php
index 84f61670bf..e46247ef82 100644
--- a/src/wp-admin/includes/ms.php
+++ b/src/wp-admin/includes/ms.php
@@ -807,7 +807,7 @@ function _thickbox_path_admin_subfolder() {
 ?>
 <script type="text/javascript">
 //<![CDATA[
-var tb_pathToImage = "../../wp-includes/js/thickbox/loadingAnimation.gif";
+var tb_pathToImage = "<?php echo includes_url( 'js/thickbox/loadingAnimation.gif', 'relative' ); ?>";
 //]]>
 </script>
 <?php