This photograph on the Library of Congress website was taken in Chattanooga, Tennessee, apparently in 1864 according to their information. It shows Confederate prisoners awaiting transport to the North at a railroad station. These soldiers were probably made captive during the Atlanta campaign, although many of the men are shown wearing great coats, so maybe the image was taken in the early spring of 1864. Lookout Mountain looms large in the background and United States Military Railroad cars sit on the tracks.
Taking a closer look by enlarging the image, shows a number of soldier prisoners trying to catch some sleep beside a depot station building. One soldier has his leg propped up on the stone wall and a number of wooden casks are scattered about. The soldier on the left of the image is just slumped over as if exhausted.
Of the many Confederate prisoners in the photograph, this one looks extremely bored and quite tired crouched among his captive comrades.