For some thumbnails I now get a 404. Not sure that if is related to the update or changes to the 404 handler? I.e. if you look at http://test2.wikipedia.org/wiki/User:JanGerber/commonstest all thumbnails currently return an error.
Files that previously had issues, i.e. http://test2.wikipedia.org/wiki/File:Citygroup_Center,_San_Francisco.ogv now look great.