The New York Public Library has a digital collection of galleries of vintage prints. There are endless possibilities. I can't decide which I like the most.
Fashion? (probably my fav)
Medical images for Stud's office?
I love all of them. And you just go on the website and can print them off. Stick them with some frames from Michael's (the best place I have found so far to find cheap basic picture frames) and voila! Planning on using some in the soon-to-be guest bedroom, so I'll update with a final product.