I highly recommend Padzzle for 99 cents. Basically it's like a jigsaw puzzle game. It comes with a bunch of hi-res pictures, but if you want, you can use your own pictures from the gallery. Double tap to turn the pieces and when they get close to the correct one they snap together. They have small and large pieces (difficulty). The small pieces are really hard; would take a long time to put together.
It took me about 10 minutes to put together a puzzle of a picture of my Camaro on easy difficulty, but I'm not a huge puzzle guy.
Great app, worth the buck IMO.