If you don't create a free imgur account, you get an option to upload directly from a URL. This is handy for rehosting images off of a 3rd party site where you don't want to steal their bandwidth when you post the image on a forum.
Once you have a free account, there's no more option to use the URL "upload." Minor pain in the butt. Would be nice to see this fixed or added.
Customer support service by UserEcho