Winter break hours being Sat., Dec. 9th. Get more information here.
Photography
Aperture Foundation Gallery:
http://www.aperture.org/gallery/
George Eastman House:
International Center for Photography:
National Geographic's Photography Page:
http://photography.nationalgeographic.com/photography/
Photoeye:
Photography Now:
http://photography-now.com/exhibition/?type=A
Society of Photographic Education:
Women in Photography International:
http://womeninphotography.org/wipihome.html
The "google" of government documents--simply type in "photographs" to access government images:
Historical collections that exist in digital format: