ayg wrote:

Not necessary in my view. This is the kind of thing best handled on a case-by-case basis. I see insufficient value to add this to the software, especially as Yet Another Configuration Option. It certainly can't be always true without a config option, either: unacceptable for small wikis, where the uploader might legitimately not feel a description is needed. Recommend WONTFIX.

If you really need to do so, use JS for checking of the upload form.