Cold hands and 19th Century Americana

I was looking at this photo of Lincoln and noticed that the two guys he's with have their hands in their jackets. Then I started to think about this pose a bit and wondered why it shows up so much in old photos and paintings. I suppose I could just google it and find out, but I thought it'd be more fun to ask the grad-student useless trivia/nonsense postulation machine. Two questions:

(1) Why do guys in old photos pose this way?
(2) Should I start posing this way in pictures taken of me?