Museums
Art Gallery of Ontario
Art Institute of Chicago
Cleveland Museum of Art
Los Angeles County Museum of Art
Memorial Gallery of the University of Rochester
Metropolitan Museum of Art
Orlando Museum of Art
Museum of Fine Arts, Houston
National Gallery of Canada
National Portrait Gallery, London
New Orleans Museum of Art
Smithsonian American Art Museum
Vanouver Art Gallery

ARTstor (database of art images via the UWLibrary)

Yahoo Museum links
(many links to art pages)

Virtual Exhibits
Mexico: From Empire to Revolution
(a digital exhibition of photography from the Getty)
Panoramas: The North American Landscape in Art