Oh my god!! Thanks a ton Muzzy!!! \o/
I've added 3 characters arts and a key art from The Witcher.
Not sure but this happens because it can not generate thumbs from high compression images; pixels in millions above 25MB each file. Rar them will accept to be uploaded. Maybe they have their limits, mediafire is kind of more pictures uploading compare with megaupload that is more for brute files without making thumbs and not having other features from mediafire, from what I see.