Wikimedia Commons
Suggestion (for discussion):
At the start of the page, perhaps in a right justified box, suggest that users rather upload their media files to Wikimedia Commons and access them from there - and direct them to a tutorial on how to do it that way.
The problem is that new users will probably find this page when searching for a tutorial on how to upload images etc. and, once doing it this way, will continue in the same way without considering the preferred option (Wikimedia Commons) which makes their media files more widely available with less of a burden on WikiEducator servers.