Index of Medieval Medical Images
Bodleian Library Manuscript Images
British Library Online Gallery
A remarkably rich and ever-growing site offering online access to the collections, tours, and exhibitions of the British Library.
ARTstor - not just art, but historic photos, buildings, popular culture; over 100,000 images
Jstor - type title in key-word search, a separate tab appears for found images (some in color
Art Index/Art Abstracts - online periodical database which indexes images in art journals separately from the articles. Since art magazines are heavily illustrated with unique images, this is a major source for pictures of art.
Oxford Art Online
includes biographies, images and background information on a range of artists. Excellent starting point for art research