So here is an app I made for WP7 called Project Mosaic, that really shows off the power of your little phone.
You can select what images it uses from your photos, album art, and contact images (facebook/twitter), and then select what image you want to create.
The resulting mosaic is rather massive - click here: https://public.blu.livefilestore.com...aic.jpg?psid=1
Once it's loaded, stand back and be amazed :P
Here is a small version of the mosaic:
That mosaic was made from this image:
Marketplace link: http://www.windowsphone.com/en-US/ap...c-a8ea9bd97ab2