Inspired by this post, I think some FAQs could use a short bit like "Your storage space contains your ScrapBook, voice posts, and userpics. If you exceed your storage space, you must delete some files (or upgrade your account) in order to upload additional userpics." 183 (voice posts) and 246 (ScrapBook) already have such a line, although they also delineate how much storage space each account level gets, so it makes sense that since userpics are also affected by this issue that it should be mentioned in a userpic FAQ or two. On the other hand, this isn't an error people are likely to run into very much, I would think, at least not with userpics.
I was thinking this should go into 98 (Why can't I upload my userpic), with 1 (how to upload userpics) linking to that bit.