I’m not sure how many places they are searching from, but Google Image is one, that’s for sure. If you want to find photo of someone via the Internet, you can try your luck at facesaerch.com. The site has a very simple interface and it only serve one purpose – finding photos for you. It might not be the most accurate, I tried searching for few friends and on most attempts the photos did appear, even though sometimes they don’t appear first in the results.

Notice facesaerch was wrongly spelt, but that’s not a typo.