Ah ok, well I think we have our answer. From
https://forums.watchuseek.com/f530/imgur-block-wus-permanent-can-you-correct-4732587.html:
"Hi xxxxxxxxxx
Thanks for writing. Unfortunately that forum has been blocked from hotlinking due to abuse of Imgur's terms of service (
http://imgur.com/tos). Imgur's ToS prohibits using Imgur as a content delivery network, which means that website elements such as buttons, banners, avatars, frames, image libraries, etc. cannot be hosted on Imgur and served up as elements of other sites. Imgur's intended use is not as a CDN, but rather as a platform to upload, share and browse entertaining images, which is why using it to serve website elements or image libraries is not allowed.
Please also be aware, that any forum that has a section dedicated to selling, such as classified are also against the advertising portion of the TOS.
If you'd like to be unblocked, please take measures to undo the functionality that caused the terms of service breach, at which point we'd be happy to review.
Please let me know if you have any other questions; I'd be happy to help.
Best,
Jacob"
It looks like imgur has decided to clamp down on people doing direct image shares. So the answer is to use a different image host.