Last modified: 2013-07-08 21:25:13 UTC
Created attachment 12503 [details] Screenshot of issue Some of the sizes displayed elsewhere are not (yet) affected. I suspect the thumbnail generator broke recently and newly generated thumbnails from now on are fixed with a white background.
https://upload.wikimedia.org/wikipedia/commons/thumb/6/60/Wikimedia_labs_logo.svg/120px-Wikimedia_labs_logo.svg.png (or local equivalent) could be used as a temporary fix.
Fixed by using rsvg and purging the old thumbs.