diff --git a/js/addcontents.js b/js/addcontents.js
index 46b54ed..969c0b2 100644
--- a/js/addcontents.js
+++ b/js/addcontents.js
@@ -148,6 +148,7 @@
 ///////////////////
 
 function image_preload(list){
+    var images = [];
     for(var i=0; i<list.length; i++){
         for(var n=0; n<3; n++){
             images[i][n] = new Image();