Found a second one, this one without hat, but taken on the same occasion. I agree with you Jinlian that Two Moons looks older than in other pictures... 1909 is the year fixed to these photos but I am not certain that this is correct.
Jeroen, i don't think that your last photo belonged to Bobtail Horse (Northern Cheyenne). There are at least two official photo of him, it's very easy make the comparison. Your image is very interesting, but i don't know his name.
Hey Charlie, I am not 100 % positive, but it was identied so by the source (unfortunately I cannot find that source anymore)... there is also some resemblance with White Bull ( see his picture in old age)... Could you post the official photos of Bobtail Horse?