Preview now can be use at both ad_banner and ad_image,however it won't run correctly if user change its ad_banner at ad_image.

app/controllers/admin/ad_banners_controller.rb

@@ -40,7 +40,7 @@ class Admin::AdBannersController < ApplicationController
   end
   
   def realtime_preview
-    @ad_banner = AdBanner.find(params[:id]).preview_clone
+    @ad_banner = AdBanner.find(conditions: { title: params[:title] }).preview_clone
     #@ad_banner.update_attributes(params[:ad_banner]).update_attributes(params[:ad_images])
   end