The Flickr Montager will take a tag you tell it, and make a montage of images matching the tag, put together to form a picture matching the tag. That really explains it badly, doesn’t it?
Stick ‘kitten’ into it, and it goes and gets a picture of a kitten. It then builds that picture of a kitten out of lots of tiny, tiny pictures of kittens, which it gets from Flickr.
Oh, just go play. It’s cute, and it’s clicky-clicky.