The Diane Arbus 'image' has become a horror cliche, due to Kubrick, and I would argue a photographic cliche due to Kubrick too. I'm sure people on Flickr have done it without knowing who Arbus is - Kubrick has better embedded the image of twins in our subconscious. Pop culture always wins in that regard. I'm a Kubrick fan, but a bigger photography fan, yet when I think of twin girls, I think of Kubrick first, Arbus second. Graphic reproductions of it are rare, partly, I would think, because the original photograph isn't graphically formal, it's more an apparition of an image - which is why Arbus' work is so beguiling.
It only seems to be photographs which are symbols for historic events or icons of human suffering - i.e. mass produced photojournalistic pictures. When you're walking down the street, a human face or figure has more immediacy than a tree or rock. You're probably unlikely to see a stencil of an Edward Weston in a New York subway. Art photography kind of works to subvert 'icons' and therefore is harder to use as propaganda.