Digital library of over one million images related to art, architecture, the humanities, and social sciences.
ARTstor (and not ACC) requires that you create a free account before accessing.
Searchable database of classic print ads. You can search by category, by decade [from the 1940s], even by year. To take full advantage of the site, membership is required.
Google image searches often work just fine, but if you want to make sure the images are high quality or avoid copyright issues, try some of these specific image sites.
American Memory provides free and open access through the Internet to written and spoken words, sound recordings, still and moving images, prints, maps, and sheet music that document the American experience.
Creative Commons provides free tools that let authors, scientists, artists, and educators easily mark their creative work with the freedoms they want it to carry. Search for audio, video, images, text, and more.
Long recognized for the stunning photography that accompanies its articles, the online site provides a photography section that features photo galleries by subject and more.
Access to over 600,000 images from primary sources & printed rarities in the collections of The NY Public Library, including illuminated manuscripts, historical maps, vintage posters, rare prints & photographs, illustrated books, printed ephemera, & more.
Has photographs and an "ImageBlender" where you can edit digital images. "Copyright friendly images for education" available for use in teacher or student projects.
The Graphics Fairy posts a free piece of vintage clip art every day, perhaps useful for your next craft project. There are more than 1,000 graphics to choose from, plus tutorials showing different methods for transferring images—a lovely example is this drawer knob project. (via How About Orange)
