I have a problem with type being mandatory, because that forces me to select something when I don't know the correct one to use. A real use case: I have some images where I think the image is either a page from the booklet (type: booklet) or a leaflet or sticker (type: other). I'm not sure though, so what do I choose? Right now my options are to not upload the image at all or to lie about which type it is.

The alternative would be to add "unknown" as a type, but since that's just a hack to get around types being mandatory, it seems better to just do it properly.

Types not being mandatory would also fit in well with a better workflow where people upload multiple images first and edit them afterwards to set all the information.