I have posted these here with Kristopher Battles permission although he indicated that they are public domain, it seemed polite to ask.
I would like to point out that he only used two Marines from the museum staff for these pictures. Not only are the uniforms they are wearing very different in color (and yes, they are both wearing WWI USMC uniforms not WWI Army uniforms) but the colors seem to change quite a bit depending on the environment they are in.
|The uniform on the left is almost a chocolate brown, while the one on the right is closer to the Forest Green color that I have read about.|
|The chocolate uniform doesn't appear quite as dark here.|
|The forest green uniform is much greener in this shot.|
|Here they are side by side, here the brown uniform appears quite dark and the other one is much closer to the WWII German Feldgrau color.|
Other reference photos most of which were supplied to me by the staff at the museum