In my humble opinion ^-^,
I think the following should be allowed:
Anime cel
Scripts
Original anime art
In more detail that means the following:
Gallery area:
Art associated with the anime production, game, or artist (lithographs, settei, cels, reproduction cels, hankens, genga, douga, original scripts, shikishi (or sign-boards), original genga/artwork, single-sheet comic art, and books, signed illustrations, or manga with autographs).
*see:
http://ekizo.mandarake.co.jp/auc_e/index.do
Private area:
Doujinshi, hentai, telephone cards, figures, posters, file folders, unsigned or non-autographed comics, books, illustrations, manga, cards and other anime related toys.
Off limits:
photos of weasels and dingos ^-^