diff --git a/static/js/Wiki.js b/static/js/Wiki.js
index 598d838..e18b972 100644
--- a/static/js/Wiki.js
+++ b/static/js/Wiki.js
@@ -1312,7 +1312,7 @@ Wiki.prototype.connect_image_button = function ( button, filename_prefix ) {
 
 Wiki.prototype.down_image_button = function ( name ) {
   var button = getElement( name );
-  if ( !button )
+  if ( !button || !button.filename_preifx )
     return;
 
   var toolbar_image_dir = this.get_toolbar_image_dir( button.always_small );
@@ -1328,7 +1328,7 @@ Wiki.prototype.down_image_button = function ( name ) {
 
 Wiki.prototype.up_image_button = function ( name ) {
   var button = getElement( name );
-  if ( !button )
+  if ( !button || !button.filename_prefix )
     return;
 
   var toolbar_image_dir = this.get_toolbar_image_dir( button.always_small );
@@ -1344,7 +1344,7 @@ Wiki.prototype.up_image_button = function ( name ) {
 
 Wiki.prototype.toggle_image_button = function ( name ) {
   var button = getElement( name );
-  if ( !button )
+  if ( !button || !button.filename_prefix )
     return;
 
   var toolbar_image_dir = this.get_toolbar_image_dir( button.always_small );