I've been working on PhotoStructure (not so much to be an imgur replacement, but as a way to automatically organize and share my large (many tb) and disorganized (due to failed photo apps and cos) pile of photos and videos. I'm releasing to a new wave of beta users soon if you want to sign up and try it out. It's a self-hosted solution with a web UI. https://blog.photostructure.com/introducing-photostructure/

As one entrepreneur/engineer to another: Don't underestimate the legal and logistical effort you'll incur from a caching CDN. People post pirated, abusive, and generally bad things, and if it's on your server, it's (becoming moreso) your responsibility. DMCA and takedowns will consume noon-trivial time, and makes simple corporate insurance decidedly not simple (or cheap). It's typical for media hosting companies to hire teams to handle these issues. I was shocked while working at CNET (way back when) when I found out most of a floor (in a large building) was for webshots' trust and safety team.