I don't have an opinion about the service, but that's why image hosts always die or end up like this. They have ongoing costs and almost no one wants to pay.
If the images go away when the user stops paying it doesn't solve the problem very well, though.
If I expect a typical image to be 1MB and get 10000 views, I could prepay 30 years of cloudflare R2 hosting with one penny. That's the kind of model I'd want when ads aren't an option. But it's really hard to build something around microtransactions like that.
The best option for that would be a more broad platform generating its revenue from multiple means, and then offering an image hosting service as a loss leader.