Photography Collection at the Denver Public Library, Western History/ genealogy Department. The database contains about 70,000 images of early Colorado.
ART HISTORY RESOURCES: Part 15 Prints and Photography
American Memory Project
Eastman Kodak Company (http://www.eastman.org/16_preserv/history.html)
California Museum of Photography at University of California at Riverside
Center for Photographic Art
The Museum of Photographic Arts
PHOTO LONDON -- http://www.photolondon.org.uk/default.asp List of photographers in London, England