TinEye is a unique reverse image search engine which allow you to search for an image to find out where it came from, and identify which web pages make use of the image, if modified or edited version of the image exist, or to find higher resolution versions.
It use image identification technology to find out origin of particular image, different higher resolution versions of image available on web or similar images from web rather than keywords, metadata or watermarks.
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 to find perfect matches. TinEye does not typically find similar images; it finds exact matches including those that have been cropped, edited or resized.
It also provide IE, Firefox plugin to let user can search images directly from a site, simply right-click on any web image and select ‘Search Image on TinEye’.Visit: TinEye (Firefox Add-ons)