Pixuffle is a fun web app that allows you shuffle parts of images to create really interesting compositions.

You start by loading a photo from your computer, and then sliding left, right, top and bottom areas of the image with a very playful interface. By doing so you cut up the picture in sections and create a unique result. When done, you can save the image back to your computer and, if you allow, let it be automatically uploaded to the Pixuffle’s Flickr Account.
 

http://www.pixuffle.net