As schild said over here we've disabled pointing your avatar at an external URL because of an unfortunate incident. Apologies to those who had to see that.
To ensure consistency I've update the handful of you that were using that feature (with no issues but we can't have nice things) to use server side avatars. A subset of that handful had their avatars "broken" because of the change and you'll be getting PMs explaining the problem in a bit.
No Nerf, but I put a link to this very thread and I said that you all can guarantee for my purity. I even mentioned your case, and see if they can take a look at your lawn from a Michigan perspective.