According to William Frassanito's book, Grant & Lee: The Virginia Campaigns the picture was taken by T.C. Roche as previously mentioned. Below is the original caption.
"Rebel artillery soldiers, killed in the trenches of Fort Mahone, called by the soldiers Fort Damnation, at the storming of Petersburgh, Va April 2nd, 1865. The one in the foreground has U.S. belts on, probably taken from a Union soldier prisoner; his uniform is grey cloth trimmed with red. This view was taken the morning after the storming of Petersburgh, Va. 1865." T.C. Roche, Anthony stereo # 3181, April 3, 1865 (LC)
Of further note is the other "dead soldier" in the background. If you look closely,(sorry this small picture is the only one I could find in a hurry), you will notice his clothes look more civilian and he looks more African American. I believe a recent article in Civil War Times or another publication found a picture of this "other soldier" who was actually an assistant to Mr. Roche and merely placed in this picture to give it more effect.
And I believe "CivilWarincolor" of this forum has already colorized another one of the views of this dead soldier.