Reddit did the right thing - they realized a majority of their users are on Reddit for the images, which makes it a core competency. Reddit was using Imgur as a free image host, which Imgur was obviously not ok with. I realized this last summer when imgur started redirecting direct image links into its ad-ridden bloated mess of a social image page. It was an obvious attack on reddit. I don't know if imgur ended up undoing this or not, but it made it painfully obvious that reddit and imgur cannot peacefully coexist in the way it used to.
edit: just found this, it looks like they're continuing to move away from being a simple image host for reddit. https://www.reddit.com/r/assholedesign/comments/6eip2q/imgur...