diff --git a/IPython/html/static/notebook/js/outputarea.js b/IPython/html/static/notebook/js/outputarea.js
index a0641391e..289858a8b 100644
--- a/IPython/html/static/notebook/js/outputarea.js
+++ b/IPython/html/static/notebook/js/outputarea.js
@@ -616,7 +616,7 @@ var IPython = (function (IPython) {
     OutputArea.prototype.append_png = function (png, md, element, type) {
         var toinsert = this.create_output_subarea(md, "output_png", type);
         var img = $("<img/>");
-        img[0].attr('src','data:image/png;base64,'+png);
+        img[0].setAttribute('src','data:image/png;base64,'+png);
         if (md['height']) {
             img[0].setAttribute('height', md['height']);
         }