Uwe Hermann | A slightly paranoid Debian developer

I found out about TinEye a few minutes ago. It's a nice little search engine which allows you to find exact copies of a photo or even similar versions of it. You can either upload an image for comparison with their database, or point TinEye to a URL of the image you want to check.

For instance, checkout this this search for my unreasonably popular "Sugar" photo. Or have a look at this list of sample searches.

The site is also used in Wikipedia for detecting the original source of uploaded images.

I know there is some other website which also allows similarity search of images, but I just can't remember the URL. Please leave a comment if you know of other such sites, thanks!