Notice the Union officer on the left.
See post #32
Don’t be so sure of that...some confederate officers uniforms were of a charcoal gray.
http://www.ushist.com/american_civil-war_uniforms_confederate_cs_f.shtml
I'm not an expert on uniforms, so I cannot be 100% sure, but those soldiers look like they are wearing CSA uniforms. The officer is wearign something darker, obviously. It might even be blue. But you have to remember that the entire federal army wore blue in 1860 (before the war). In the early battles, there were quite a few men in blue fighting for the South. It was confusing.
I believe that photo represents a Southern unit, and I believe the officer is CSA -- but I'm not an expert.
and how do we know for sure your photo is not an internet photo shop fake?