Maggie Dennis on bug 50645:
I'm not sure if this is the same issue, but as reported on English Wikipedia
and tested by myself, using the image resizer to "Make full size" resulted in
either a notice that no change had been made or a silent failure to save.
The reporting editor concludes that "These new settings, for what they are
worth, only work if the image already has a size indication (200px,
250px*250px, whatever), not when it only has a 'thumb' indication. Sadly, the
latter is the default and by far most common situation."
He also questions the purpose of "Make full size", but I'll report that