Drag & Drop between canvasses in App

I am looking for some sample code to allow my app to drag a picture from one canvas on screen to another. My app has a collection of 8 canvas controls (a set) to form a picture gallery.
I would like to be able to re-arrange the pictures by dragging/dropping between the canvas set members.
All the examples I have found are for dropping pics into the app canvas from outside, which I have working just fine.
Thanks in advance