I don't want you to think your being neglected but I for one NO very little about the photographer Alexander Gardner other than his training appeared to have come from Matthew Brady himself. I know that Andrew Jackson Riddle took some infamous photos of Andersonville prisoners in August of 1864 could Gardners photo have been to show its readers how well the Southern prisoners were being treated? Battles and Leaders were in four volumes usually listed by periods of the War. Did the work appear in Volume 4 for example? If so I think (If my memory is correct) Volume 4 dealt with the period from early to mid 1864 to the end of the War.