Flickr Commons is a collaborative project that allows cultural heritage organizations, such as the Library of Congress, the Smithsonian, and several dozen other museums and archives, to make their materials more easily discovered. Through the Flickr Commons, those organizations get direct feedback from the public about their materials, as well. All images are published with "no known copyright" restrictions and are part of the public domain.
Contains free high resolution digital stock photographs and reference images for either corporate or public use. The site's purpose is to provide free image reference material for illustrators, comic book artist, designers, teachers and all creative pursuits. The current license allows for use and remixing without attribution, but prohibits you from selling the images or claiming ownership.