Search Images Online using TinEye
TinEye is the new image identification search engine which was launched recently by Idee Inc. It is not like Google Image Search where you specify a name and Google will display the images. Here, you will have to upload an image and it will search the Internet and tell you where that particular image (with slight modification) is being used.
It can even find photos similar to the image you have uploaded. It creates a digital signature of the uploaded image and compares it with all the images which are in its database. It can also detect images which are part of the collage and are blended with another picture. Currently it indexes around 701,666,310 images from the web which is quite small. However, the number will grow as time progresses. You can also install thee browser Plug-in which will allow you to search for images with the click of the mouse. This new service has a lot of potential. I would be happy if they include an option to search for the images of the same person whose image you upload.
At present, it will be useful for users and artists if they want to check where there images are being used. I am certainly keeping an eye on this service, it looks like it has a great potential. It is currently in Private Beta. You can request an invite here.