More specifically, this is President Lincoln meeting with General George ‘Little Mac’ McClellan in the General’s tent at Antietam in September 1862. McClellan was leader of the Army of the Potomac, and a world champion procrastinator/overthinker.
The photo, btw, was colorized by Laiz Kuczynski, who says, “A lot of guesswork goes in to colorization, there’s no way around it, but a lot of color can also be surmised simply by the black and white hues. Red will show up more obvious than light blue, for instance, on the original B/W exposure, so ignoring historical research and verifiable evidence and contemporary accounts, guessing on the B/W hue is actually a solid guess post-19th century. Also I’m hitting the bed, so I won’t be able to answer questions until the morning here!”
Spoiler: Lincoln dies at the end of his vampire hunting days.