That is a shame. Right now my wiki is looking like it is fast approaching its upload capacity and if what I am looking at on my Recent Changes trend continues more than half of the space used is wasted space because users, not knowing what their articles will look like, often re-crop their images after the initial upload to better fit our templates, especially if it is their first time creating articles.
File manager says we have some 1,300 files… I KNOW we don't have that many articles and each article only has 1 field for image uploads =/ If not some way of detecting logical links and file references in articles how about a simple server-side last-accessed level tracking and the ability for admins to set some sort of housecleaning function.
Sure, its possible for an article not to have been read for +2 years and used files might be accidentally cleaned but if they got caught in that net then obviously the files weren't that important and maybe that is something for the wiki's staff to decide, how aggressively they want to do their cleanup.
File space is a genuine concern because our Wiki's growth has been ecstatic. We are less than a year old but have some 400+ users and +800 articles ever since our community's mass exodus from our previous Wikia powered wiki. Our Wikidot experience has been going great but that growing %aged used of cap will be a genuine concern going forward.