There's an even larger collection here:
http://www.greatwar.nl/
Click on the left under "The First Real Color Pictures of World War I"
Caution. Some of the other galleries have very disturbing photos of dead and mutilated soldiers particularly a raped Russian female soldier. WWI was more brutal than most people realize.
Great link. Will check back later.
Ya'll may find this of interest. The original article links don't work, but current links can be found in posts #35(more extensive collection) and #129 (the first link at 129 has bigger pictures.)