Yesterday, during upload of this file:
https://commons.wikimedia.org/wiki/File:PL_Jean_de_La_Fontaine_-_Bajki.djvu
I have got "system under maintanance" error message. After that (as a result of the error?) some thumbnails of pages from this file were not updated. Especially, one of them:
https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/PL_Jean_de_La_Fontaine_-_Bajki.djvu/page657-1024px-PL_Jean_de_La_Fontaine_-_Bajki.djvu.jpg
is critical for Polish Wikisource.
Please advice, how can we update it, or clear it manually in the cache.