Common behavior from overloaded servers. That's coupled with the Internet name servers either being "poisoned" (incorrect address resolution) or the name servers are just being hammered by requests for imgur and are defending themselves (its similar to a DDOS attack).
The way to band-aid it temporarily is to find out what the numeric IP addresses are and add them to your computer's "host" file (buried deep in the operating system folders).
People can google for how to find and modify host files on their computer and they can google how to determine the numeric IP addresses of websites.
I pull up a DOS command screen and type "ping imgur.com". The response is 54.243.206.51. It is currently timing out (pings are dying a lonely death).
That tells me that modifying my hosts file isn't going to do squat because the imgur server is not connected to the Internet (on fire, power off, network near it is hosed/cut, etc). Time to go play Torchlight
