The sites below offer excellent images for research in art and art history and are especially good for illustrating a research paper or creating a class presentation. See the Web Resources tab for many other resources.
African & Asian Visual Artists Archive
Library of Congress Digital Collections
Bridgeman Art Library
Visual Arts Data Service (VADS) -- A well-designed site with focus on fashion, craft, 2D design, and contemporary artists working in the UK and internationally. Repository for many specail collections in the UK.
Web Gallery of Art
Cybermuse
Flickr Commons Project -- The Commons Project is a collection of medium and high resolution imagery contributed from archives around the world, including the US National Archives, OSU's Archives, NYPL's Archives, and many many more. The photos contributed to this have no known copyright restrictions. Read more here. However, many of these images explicitly state they are for educational use only, and some state they may not be modified (ex: Smithsonian). Read the rights statement to be sure what you can and cannot do with these images before using them.
Creative Commons -- The Creative Commons is a way for digital content creators to license their work for use by others online. There are multiple creative commons licenses. The pdf attached to this page lists and explains these licenses.
Every Stock Photo -- Search engine for free stock photos licensed under Creative Commons, public domain, GNU, or custom free licenses.
MorgueFile -- Free high resolution images for personal or commercial use, under this license. You can filter your search by size, color, geotag, and more. From the site: The purpose of this site is to provide free image reference material for illustrators, comic book artist, designers, teachers and all creative pursuits.
Library of Congress Prints and Photograph Collection -- The Library of Congress Prints and Photographs Online Catalog offers digital images of much of the Prints and Photographs Division’s holdings including architecture, design and engineering, among other categories.
The ARTstor Digital Library is one of the premiere image databases for research in art and art historical topics. It includes more than 80 collections of over one million images. The collections are gathered from a wide variety of museums, research collections, artists and artists’ estates, library special collections, and photo archives. Content includes images from the fields of art, architecture, material culture, maritime history, anthropology, and archeology. The collection is available for non-commercial and educational use only through the Library.
ARTstor is not only a rich digital library of art images and descriptive information, but also provides software tools to enable active use of the collections. ARTstor's search interface allows users to view and analyze images through features such as zooming and panning, saving groups of images online for personal or shared uses, and creating and delivering presentations both online and offline.
Help in using ARTstor is available at http://help.artstor.org/wiki/index.php/ARTstor_Help_Topics.
Imageafter
20,000+ images. There are two drop-down menus (one for textures, one for images) for category browsing. Imageafter allows you to use their images on printed material for resale.
WorldImages
Access the California State University IMAGE Project, containing 60,000+ images. Global in coverage and includes all areas of visual imagery, its images may be freely used for non-profit educational purposes.
Imagebase
The photos on Imagebase are free to use, and are licensed under a Creative Commons license.
Stock.xchng
Owned by Getty Images, 350,000+ stock images for use, keyword searchable. Non-commercial use only.
Free Use Group on Flickr
1200+ random images contributed by Flickr users available for unrestricted use.
This is a video database in which you can watch various dances.