A New Kind of Search-- Reverse Image Search

Tineye.com is a very cool search tool. 

You upload an image and then it searches from a database of over 2.2 billion images. 

Have an image you'd like to use but not sure of the source or permissions? This search tool could be a handy way to find out whether you can use it-- or it may show you that the image you are using is a cropped portion of a larger image. 

There's also a widget you can add to your browser tool bar so you can look up any image on any webpage you land on.