When you make an item page, please make sure the image is renamed to "Item Name.png" without the numbers or other things. (I've got a billion things to rename >:U) Use the {{Infobox item}} template I Just made and fill it out, it automatically adds proper categories to the page.
Anyway I'm off to bed, will do some more housekeeping tomorrow!
Edit: Because of how many files are already uploaded with item IDs, we're just going to stick with that. But please do use the new infobox template.