Not wanting to sound morbid, but how DO I cut up a picture? Does it involve some retouch, to restore some parts that were hidden from view by e.g. an arm? I photographed this from a glossy magazine as an example.
If you're working with an existing picture, then yes, it will require restoring some parts you can't see in the original. If you're shooting pictures, I would position the model so that none of the important parts you want to move are hidden (hold their arms out to the side, for example).