Louise Brooks, from the cover of her 1940 pamphlet, "Fundamentals of Good Ballroom Dancing." I've cropped at 3x5 aspect ratio, and added some crosshatching to cover up the artifacting of enlarging the image.

I've been doing a lot of cropping of images the last day or two to an aspect ratio of 3x5, which most closely matches my laptop's screen resolution of 1680x1050. I've both tagged them with "3x5" and created a set.