TinEye , by Idee Labs, is a reverse image search engine that tells you where and how an image appears on the web, even if it has been modified. This ground breaking technology lets you submit an image, or a link to an image, to find where online the image exists.
Take any saved image (try saving this William Bradford painting to your desktop), and then navigate to the TinEye search tool and upload the file. I did just that and in less than one second the software searched over 1.1979 billions images returning six matches.
The pixels that comprise the image are the objects used by the this search engine. Just as Google, or any other search engine, uses words to find content, TinEye uses pixels. Amazing!