Unidentified trooper taken by an unidentified photographer. My guess is that his sword is a model 1840 " wristbreaker". That thing is HUGE! From the Liljenquist Collection in the Library of Congress.
It is a great image. He is carrying a model 1840 artillery sword that is partially (about 6 inchs) pulled from the scabbard. The blade on the arty sword was 32 inchs long so I'm leaning he is ridding a pony.
If he's so short, that must be a mini-horse! Looks to me like the sabre is drawn nearly half-way, and the top of the low-slung scabbard is about at his thigh.