How to show loader image before popup screen of color box module in drupal 7
Hope this will help you,


You can use Colorbox Callbacks


onOpen : Callback that fires right before Colorbox begins to open
onComplete : Callback that fires right after loaded content is displayed


jQuery.colorbox({ 
........
  onOpen:function(){
    //show loader
  }
  onComplete:function(){ 
   //hide loader
  }
});