Special:Upload prepends "== {{int:filedesc}} ==" to file upload pages. If the filedesc message has been deliberately changed from its default value ("Summary" in English) to a blank value, then do not prepend any title at all.
Currently, if filedesc is blank, then the file upload page is prepended with "== ==".
Note, as per matthiasmullie's comment on T187302, it used to be possible to default to no title until his change of 6 Mar 2018.