Currently imgur fails to serve images over ssl:
> LANG=C curl -v https://i.sstatic.net/yurfY.png
* Hostname was NOT found in DNS cache
* Trying 54.197.236.143...
* connect to 54.197.236.143 port 443 failed: Connection refused
* Trying 54.221.248.15...
* connect to 54.221.248.15 port 443 failed: Connection refused
* Failed to connect to i.stack.imgur.com port 443: Connection refused
* Closing connection 0
curl: (7) Failed to connect to i.stack.imgur.com port 443: Connection refused
Without ssl the images work.