That's literally what they did for years until taking a16z's money...
They did it by building a community around the non-reddit related traffic. Basically redditor's would share imgur links outside the reddit ecosystem (Facebook etc), then other people would visit imgur directly instead of going through reddit. These secondary users are monetizable.
Imgur had to eat the costs of supporting reddit's hotlinking (though not all reddit posts are hotlinked) but that was more or less imgur's "marketing budget."
They did it by building a community around the non-reddit related traffic. Basically redditor's would share imgur links outside the reddit ecosystem (Facebook etc), then other people would visit imgur directly instead of going through reddit. These secondary users are monetizable.
Imgur had to eat the costs of supporting reddit's hotlinking (though not all reddit posts are hotlinked) but that was more or less imgur's "marketing budget."