Using drag and drop to build an image

I'm trying to build a cake dragging some items to it, and then that I can download the image with all of the items dragged, But I don't want the image of the item disappears , I want that count every time that I drag it. Has anyone built something like this before? I need an example please, I have to do it in javascript or Jquery.

This is my gui: http://ift.tt/1GXNNAJ