What you'll need:
A printed out image
A Box Cutter
Hot Glue Gun
Duct tape (of course)
Also, my image is relatively simple, but if you want to use one with spereate objects, use this tutorial with mine.
Oh, and this is my first instructable, so be constructive, but not too harsh.
Step 1: Preparation
Print out whatever image you want to use, and tape it to the foam board.