I’m not sure, perhaps the rest of the world has already known about this site for ages, and I’m just slow to notice it? Anyway, if you have an image on your site that you suspect others have stolen and used without permission or credit, or if you have seen a picture that has been photoshopped, and want to find the original, try out TinEye. Also useful if you’re trying to find a higher resolution, or original creator of a photo. The index is still relatively small, so you can’t take a result of 0 matches as conclusive proof the image doesn’t exist elsewhere on the internet, but fun to play around with, anyway. Reverse image searching is the correct term apparently. If you would like to read a better phrased, official explanation, see the text below.
TinEye is a reverse image search engine. You can submit an image to TinEye to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions. TinEye is the first image search engine on the web to use image identification technology rather than keywords, metadata or watermarks. For some real TinEye search examples, check out our Cool Searches page.
btw, no $ involved with this post, just came across the site and thought others might find it interesting.