My profile icon changed this morning without my doing. Is this a known issue on the SE network? I liked my old blue-colored design. Is there any way to recover it?
This has happened elsewhere in the network, I saw it here (as well as for this Physics moderator) and there is also this on the mother meta. I'm not sure why it happened, or even if it's internal to SE or an issue with Gravatar, but it seems to have affected a lot of people.
The only way I know to get it back is to Google or Bing your username and hope that the old picture is still in a cache somewhere. In your case, the old picture looked like this if I remember correctly:
You can now just load that directly.