Stack Overflow's hosting is managed by Imgur, but it's no longer integrated into the Imgur website in any way. There's no reason to be under imgur.com
, a domain that's likely to be blocked by many internet filters because of the amount of porn it hosts.
Switching to something like http://i.sstatic.net/
should fix this problem. (Imgur uses EdgeCast so IP-based blocks are unlikely.) It would also make their URLs host-agnostic, preventing the need for any more mass-replacements of URLsmass-replacements of URLs after this one.
...but for all we know this might violate Stack Exchange's deal with ImgurStack Exchange's deal with Imgur and be impossible for now.