I asked for some help identifying the uniforms in this picture on the Info-Ukes genealogy mailing list, and got a number of helpful replies, but one problem was that the picture of Sobol and his friend was too small to see insignia and the like. So here's a page of close scans of some items that might help identify the uniforms. [It did, but not through Info-Ukes. Mark Conrad identified some of the items on this page in June, 2001.]
The scan at right is of the medal being worn by the man on the right of the picture carrying a rifle. Because of the size of the picture, it's hard to get the ribbon any clearer than this. It's hard to tell even which alphabet it's in, but the fourth line looks to me to be an acronym, with the first letter possibly an "L" and the third letter possibly a "T".
Mark Conrad says: "The ribbon/medal for the man on the right is some kind of civilian commemorative thing, not a military medal."
Stan Broski on the list posted a very helpful message that mentioned that enlisted men would be photographed with their rifles, but officers with their swords. If that's the case, then it would appear that Sobol was an officer in whatever army he was with, because he is in fact carrying a sword, something that escaped both me and Stan at first glance.
Sobol is also wearing some sort of medal. No idea what this is.
His friend is wearing two different insignia, one on his collar and one on his hat. The one on his hat (at right) is of a pair of crossed rifles. The one on his collar (at left) is of a pair of crossed swords.
Mark Conrad explains the insignia:
The (backwards printed) enlargement of the hat device is the crossed rifles of the infantry, indicating E company of the 8th (?) Regiment. Whether it would be US Army or some state's National Guard would be indicated by the collar insignia ("US" for regular army, and for National Guard a state abbreviation, although Pennsylvania used a keystone shape). Most states did not go up to "8" in their national guard, but the regular army and large states like Ohio, Pennsylvania, and New York did.
The final item is the beltbuckle worn by each person. This is the one worn by Sobol, but the enlisted man next to him is also wearing the same buckle.
Mark Conrad's comments: "The enlarged belt buckle is a not regular army for this period, but might be from an earlier era. Regulation at this time was a simple hollow frame buckle with no insignia."