jigsae puzzle issue

[Joseph King]

Hey i am trying to build a puzzle (jigsaw) game.  I have most of the 
code for it written in python.  But having an issue with one part.

What i want is to give the player the ability to import there own 
picture and create a jigsaw from the picture with there own designation 
of the piece size and shape.  I am having difficulty with one part of 
how to let them create the piece and then give it the ability to link 
the pieces together so the user knows that they have the right two 
pieces placed together. I want to try and make this a free standing 
picture that later can have things integrated into it with out much 
difficulty.