Hard to believe the North won looking at that picture,, The setting is not 1864, but in the first few months of the war, I assume he painted it in 64. Nice find!
Strangest thing... I was personally in the Cleveland Museum of Art one week ago and stood 2 to 3' away from this very painting! I asked if I could take a picture and they said yes, as long as I didn't use a flash. The colors in person were absolutely vibrant. Here is my photograph of the same:
Also in the same museum on the same night, this painting by Pierre Bonnard, Cafe Terrace, 1898:
I'm pretty sure those were in name only after the first few months of the war. The Smithsonian credits the uniform to the first year of the war. Could be wrong though, I'm from Atlanta.
I'm no expert, but I was a bit of a Civl War buff as a kid. I think those units were used for more than just the first few skirmishes, but eventually they dropped the sexy outfits.
It's possible the pipe may not have been a briar, but the clay pipe that was common amongst enlisted men on both sides, as for example this one I got on an archaeological dig at Appomattox.
Cool Painting! I believe the Union Army had Zouave units at least through Gettysburg. There is a monument there to a Pennsylvania Zouave unit(forget which one). The Confederacy also had a Zouave unit in Wheat's Tigers out of Louisiana. They were more or less shock troops. I forget exactly when they ditched the funny uniform but I think it was in 1862 or early 63.