Ulysses S. Grant in Mathew Brady’s studio sometime before his presidency, ¬†wearing his 4-star shoulderboard with the rank of General of the Army, definitively making this after the Civil War ended. You can see a wide range of props used in Mathew Brady’s studio, including a moveable backdrop that extends way beyond the curtain (also moveable I assume), together with an actual lamp in the ceiling, and probably many other things out of frame.