+1 everyone else, just a couple additions: you're not meant to button the bottom button of your vest. For length - the easiest rule of thumb is simply that when looked at from behind it should cover your butt. Yours looks to be several inches short of this. The current fashion trend is towards jackets shorter than this rule, but even if you're going for that look (which will mean you'll look hilariously dated in a few years, note), it shouldn't be THAT short.
4/23/13 at 4:35pm