Wikimedia Commons and Flickr Creative Commons provide large databases of free downloadable images with varying use restrictions. Many U.S. government websites offer public domain photos for free download, such as the National Gallery of Art and National Aeronautics and Space Administration.
Wikimedia Commons and Flickr Creative Commons allow users to search for images by topic or specific name. Both websites contain photos licensed for various levels of use once downloaded, ranging from public domain photos that allow for unlimited use to creative commons photos that allow only personal, non-shared use. Individual photo landing pages on both websites list the license for the specific photograph and provide descriptions of the different uses allowed with each type of license.