In the advanced search tab of Google Images you can now specify: all content, news content, faces, and photo content. Photo content is the new addition. You can strip put illustratations, logos etc. from your image search. (Thank you  Lifehacker.) Although I purchase all my PowerPoint images from stock photography sites, I often use Google images to "brainstorm" a concept for an image. Off topic. The "faces" option might be the most interesting. We are heading for a world where images of people are getting automatically tagged, that means: all images available on the web. For fun, see MyHeritage that has developed technology to match your face with that of a celebrity. My face was matched to that of Formula I racer Alain Prost. I guess their technology will be put to more serious use soon.