additionally, for those wiki's that host things from official channels, officially approved, like officially approved game wiki's, they could get approval of the copyright owners to use the avatars. In example, on yppedia (Puzzle Pirates official wikipedia), players can upload portrait photo's of their characters and crews. These are all in-game images and approved to be included in the wiki. The wiki is maintained by both the players and the ones who are managing the games.
For me personally, I am creating a game as we speak and setting up a wiki for it, so that it will be there when players start playing the game. I will give them the option to upload screenshots and portraits and such to the wiki, as well as offer avatars.

@SamanthaNguyen I understand that those folders in that location are the most logical place. I'm not debating that. I too find that the most logical place. That was not my question. I don't mind them being there. I don't mind them having contents already either.

You're welcome :)
Sorry, Apparently I was editing my original post with extra info while you edited my title and replied :)
I've also included the steps I took.