Thread:Project:Support desk/subdirectories /images in mediawiki 1.9

I changed the server and updated from 1.10 to 1.19. Now my wiki doesn't find the pictures anymore. The error in german:

"Fehler beim Erstellen des Vorschaubildes: Datei scheint fehlend zu sein: mediawiki-1.19.23/images/1/1f/Mannheim_Atlantis.jpg"

In the old version the pictures are in /images but now there are subdirectories /images/1/1f etc. And because there are a lot of them, I don't know in which I should copy the photos.

Is there a reason for these directories and can I change it back to /images?