Everystockphoto is a license-specific photo search engine. Currently they index and search millions of freely licensed photos, from many sources, and present them in an integrated search. They make an effort to show as much information as they have about particular photos on the photo page, including source, license, dimensions, photographer, and other data. The license is almost always shown below and left of a photo, and clicks through to the specific license page. Membership is free and allows you to rate, tag, collect and comment on photos. You can add your favourite photos to your collections as well.
License: See Individual Images