Let’s say you have an image file, that you are interested in, and the filename is not really giving much information about the source of the image, how you can get more information about the image? What I normally do is to describe the image using the best words I can think of by looking at the image, and search for those words in Google. This is not a very good method, and sometimes didn’t guarantee good result.
From now on, you don’t have to worry about the problem above, or use my method of searching about the image. Google has launched the Search by Image (http://images.google.com/). Watch the video to get the idea of this new Search by Image.