The use of digital images is often subject to copyright and/or licensing restrictions. Consult each site's information on rights and reproductions, especially if you plan to use an image in a publication. It is equally important that you cite images properly. See the "Copyright resources" and "Citing images" sections.
A very large subscription-based database; offers images pertaining to the arts and related disciplines: anthropology, archaeology, history, etc. The images are of high resolution and generally good quality and are always accompanied by descriptive metadata. Searching is by keyword and can be limited by date, location, and medium, or specific collection. Images can be resized, saved, and downloaded.
The Visual Resources Center's ImageBase contains approximately 200,000 art historical images. In addition to the quick search box, you can explore by browsing collections that have been sorted by department, faculty name, medium, country, and style.
Maintained by San Jose State University, the WorldImages database provides access to the California State University IMAGE Project. It contains approximately 100,000 images, is global in coverage, and includes all areas of visual imagery.
Archives of American Art Image Gallery
A subset of the Archives of American Art's Collections Online, the images collection includes photographic images of artists, exhibition installations, manuscripts, and events.
The Athenaeum is a crowd-sourced collection of approximately 50,000 images. Subject matter is currently limited to European and American paintings and works on paper. Copyright and fair use advice accompanies images for which these conditions apply.
Visual Arts Data Service
A UK-based source for art historical image collections, the VADS site brings together resources from British cultural institutions for the purposes of access and preservation. It is particularly strong in the areas of material culture and design. Copyright restrictions vary by collection; ample explanatory information is provided.