American Photochrom Archive
Over 1300 vintage photochrom images of the United States, Canada, Mexico, and Cuba mainly by noted photographer William Henry Jackson.
www.photochrom.com
NPS.gov: William Henry Jackson
Profile of William Henry Jackson, best known as the first person to photograph the wonders of Yellowstone.
www.nps.gov/scbl/whj.htm
Wikipedia: William Henry Jackson
Profile of the American painter, photographer, and explorer famous for his images of the American West.
en.wikipedia.org/wiki/William_Henry_Jackson