[Request] Can someone help me vectorize these Game of Thrones images?

I found a couple GoT images that I would like to turn into posters, but the image quality is a little on the low side. I was thinking making them about 12'' x 16'' or maybe even 16'' x 20''. Can someone vectorize these for me? Would that even be the best way to go about this? Thanks in advance.

http://imgur.com/a/S28M9