IMGUR was actively blocking our use here for a while. When VTAC came back for a short time he made some kind of agreement with them and got them to stop blocking us, so it has been working since then. Because I lost access to so many pictures I had hosted there (like I did permanently at Tinypic), I don't have a lot of confidence that something won't happen again, so I have been continuing to use IMGBB for the most part. I did do a test in here the other day to make sure IMGUR was still working and it is.
These are free services, so without recompense I can understand why they don't really care much about us when they decide to go. In truth, I keep a copy of anything I post to those services just in case they are disappeared again or access is disappeared. The links on any photos that they're hosting, however, will just die when they disappear. There is no way for us to go back and reassociate them with another service.