In searching www.civilwardata.com I found records of Jackson L and Henry E Garrett as being in Company F, GA 11th Infantry Regiment. They seem to have enlisted at different times, one in 1861, the other 1862. Also in Company F was an A.L.Garrett enlisting in 1863, and who deserted a few weeks later. Was he possibly a sibling or cousin?

Lots of other Garretts in the 11th regiment,2 in Company E and 4 in H; possibly relatives of your ancestors?

p.s. I forgot to mention, MI did not have any photos from Smith's Battalion, nor did they for the 65th Infantry Regiment that Smith's joined later in the conflict.