Somebody else's background image appears after uploading animated GIF.

I tried to upload the following animated gif: http://static.zeitgeisty.net/sterne.gif

A notification popped up I didn't read (must have been the one telling me that animated GIFs are not supported). However, I tried it for a second time and a completely unknown background image appeared on my profile page (see http://a3.twimg.com/profile_backgroun...). I have never even heard about "ROBYN" and this is not the image I way trying to upload. A number of people confirmed that they saw the same strange background image. I tried it with another account of mine (see http://twitter.com/KaiUhlemeyer) and then I got this one http://a1.twimg.com/profile_backgroun.... They've all got the same file name "sterne.gif" in common. That's probably the sticking point.