The links below are to digital image libraries that facilitate finding images that are either out of copyright, licensed for use, or have clear terms of use. Always check the image's copyright / terms of use before using.
Creative Commons SearchCC Search is a tool for finding openly licensed and public domain images.
Digital Public Library of AmericaDPLA connects people to the riches held within America’s libraries, archives, museums, and other cultural heritage institutions. All of the materials found through DPLA—photographs, books, maps, news footage, oral histories, personal letters, museum objects, artwork, government documents, and so much more—are free and immediately available in digital format.
EuropeanaProvides access to over 50 million digitized items
Flickr Commonsphotos from institutions that want to share their digital collections. These tend to be historical images whose copyright has expired or government images that are automatically in the public domain since taxpayers have technically already paid for them.
Google Images Advanced SearchFor copyright permissions, use the Usage Rights drop-down menu. Click the Usage Rights link for more information about the permissions of each category.
New York Public Library Digital Collections884,351 items--prints, photographs, maps, manuscripts, streaming video, and more--from The New York Public Library's collections.
PixabayOver 1.611604 million free to use images and videos
Smithsonian Open Access3 million open access 2D and 3D digital items from the Smithsonian's collections
