The page that the pic was originally on (via the link) cited Gardner's Photographic History of the Civil War (I'm messing up the title) but when I looked through the two volumes on the LoC site, I didn't see that pic. The text on the pic's page said it was Plate No. 10.
Does that woman on the far right, seated, have a rifle or musket?
I'm trying to figure out if the women are from the Sanitary Commission or nurses or what. Matching dark dresses, and the central lady looks as if she's all business with the kepi.
There's a fellow in the middle back on the right (next to the lady with the long tie/neckscarf) with what looks like an easel.