Mozaker is a sleek-looking (albeit Flash-heavy) website which uses the Flickr API to create collages using existing photos on Flickr. To choose the primary image whose mosaic you need to create, you can either browse through existing photos on Flickr on the basis of their tag, or upload your own photo. After that’s done, you can start the mosaic-ing process, which will look up random photos on Flickr to create the required mosaic. Get some really psychedelic photos using this! A really good demonstration of the neat stuff developers can cook up using the Yahoo!’s Flickr API.