[jaredmosley]

Then, assuming those kinds of images are against your TOS, then you ban them. This drastically reduces the number of images of that nature that are uploaded not only by ensuring they can't do it again but also by heavily disincentivizing them from doing it in the first place.

[alistairSH]

Beyond that, if the content they post is illegal, there's a more clear path to prosecution than if the content is posted anonymously.