TinEye Image Search

Image search is a hard problem. That is especially true when you are searching with no information other than the image itself (no tags, titles, or descriptions, just the photo). You can upload any image file to TinEye or paste in the URL of an image in the search box. It then will scour the Web and find sites that contain the same image (see video). As long as the image has been indexed by TinEye, it can be found. It only launched earlier this month, but so far TinEye has indexed close to 750 million images on the Web, and should reach one billion sometime next month. Google, in comparison, is estimated to have indexed between 4 to 6 billion images. At this point TinEye still is not much more than a technology demonstration. After all, most people search for images by putting in a keyword that describes it, not by showing it the image they want. (If they already have it or know where it is, why do they need to look for it?). Its main appeal right now is for photographers and photo agencies who want to find out where their photos are being used on the Web.
http://www.techcrunch.com/2008/05/26/mr-jobs-heres-an-idee-for-you-put-tineye-image-search-into-iphoto-500-invites/

http://tineye.com/