Last modified: 2012-02-26 21:19:29 UTC
https://upload.wikimedia.org/wikipedia/commons/thumb/f/fb/718smiley.svg/120px-718smiley.svg.png is broken currently. Purging the file description page on Commons seems to have no effect (i.e., the thumbnail is not being forced to be regenerated).
Hrmph. And now working again. Marking this as resolved, though there seems to be some continuing underlying issue regarding broken thumbnails being generated (or possibly cached somewhere).