TinEye is an awesome ‘Reverse Image’ search engine.
They can locate and deliver images based upon an original image URL supplied by the user.
They also have an embeddable widget that will display a mass of images found for various searches. Each photo has a link to the site where its located as well.
How does TinEye’s reverse image search work?
TinEye is the first image search engine on the web to use image identification technology rather than keywords, metadata or watermarks. TinEye regularly crawls the web for new images, and we also accept contributions of complete online image collections. To date, there are 1,572,822,693 images in our image database.
When you submit an image to be searched, TinEye creates a unique and compact digital signature or ‘fingerprint’ for it, then compares this fingerprint to every other image in our index to retrieve matches. TinEye can even find a partial fingerprint match. Our fingerprinting technologies have been developed by Idée Inc.
TinEye does not typically find similar images (i.e. a different image with the same subject matter); it finds exact matches including those that have been cropped, edited or resized.
Check out TinEye today: http://www.tineye.com/
Grab the TinEye widget here: http://www.tineye.com/widgets/display