I can't find the reference, but IIRC he (the founder of Imgur) didn't make any money for the first couple of years, as the bandwidth costs were crazy high. But he was happy to do so, because it helped the community there.
> Without this support and the growth of unlimited bandwidth servers
Without the support of his community he wouldn't have made it. I also remember him saying something along the lines of "I make no money to pay for bandwidth if you reference the .jpg file itself, but I still allow it. So I simply just ask the community to use the Imgur URL". It became part of Reddit culture to do the latter, because the users valued the service.
TL;DR - Provide a valuable service, don't piss of your users, and you can actually make some money.