I checked the Illinois in the Civil War site and there are no photo's of the unit or of Mr. Fleming posted there.
I did find that he was from Shelby County Illinois, enlisted initally on 12/01/1861, was mustered in on 2/18/61 at Jonesboro, Ill. by Captian Roessler. Was promoted to 1SGT at some point and then on 11/22/62 he was promoted to 2nd Lt., on 7/17/63 he was promoted to 1st Lt.,on 7/9/64 he was promoted to Captain and then something happened and on 12/22/64 he was discharged for other than honorable reasons. That can mean a lot of things. He obviously was a good trooper or he would not have had the promotions that he had previous to the discharge. About that time they were attacked by General Shelby with 4000 thousand troops and 4 pieces of artillery. Captaian Fleming was not in the action as companies F and H were guarding a part of the railroad that was not attacked. I don't know if that means anything or not but you might check the OR's cocerning that time and this battle and find out more.
Hope this helps