Well, considering they said no back during the ARR Beta Test for a similar idea (the use of player custom artwork for FC logos), and the reason given is applicable here as well, I don't see it happening. And that is because of human nature being what it is, someone is guaranteed to think it funny to use an image that is either offensive, harassing or a copyright violation and thus would violate the Terms of Service.

Accordingly SE would have to dedicate development time and resources to screening every piece of art that would be used for such content, resources that could be spent elsewhere. Hence, it is highly unlikely sadly, as much as I would love to be so.