George,
There is I believe a museum in Chattanooga at the military park. However I just went to the Chickamauga Battlefield. There I did not see any pictures of your ancestor. Like I said it may be over there in Chattanooga. Just wanted you to know that I did check out that center at the Chickamauga Battlefield for you. I just got home to Ohio. Going to get a little rest, take care.
Cump.