You know that hosting services talk about unlimited, but there is always some kind of limit. I preferred to have unlimited disk space and bandwidth.
I remember the time when there was a boom of unlimited hosting ads from companies like Hostgator, iPage, Bluehost and I wanted to make a file sharing website, similar to wetransfer and I was always receiving warning from these hosting companies that I shouldn't upload or store high size (500MB and higher) files on my website and when I was asking them then why it's called unlimited, they were telling me that it was marked as unlimited because most businesses upload some kilobytes and they don't limit them, etc. They were just saying it's unlimited while it was actually almost as limited as free web hosting. That's why I always prefer dedicated server but in your case, AWS S3 is really the most cost-effective option.Btw as far as I know, digitalocean doesn't have inodes limitation.
I see. That's tiny 
It's not that tiny, for the service in question. Especially at this early stage.
You have gathered 800k from a hosting, let's imagine that there are more than 800k together with the other services. Which indicates 1600k images listed from the forum. Let's round it up to 2000k images.
This is a large number, but it was gathered over 13 years, which averages out to 150k images per year. Let's round it up to 200k images per year.
That means I can maintain these conditions for the next 2-3 years. It will be time when I'm planning to do a new upgrade.
But, as I said, I'm evaluating several possibilities, we'll see what I get.