Since there is no money on a Pet project, I thought about an alternative version: to raise my own server (now in Russia there are offers for ~ 200 – 300 rubles per month and in the world, all the more fully, and for this money, even Not a particularly powerful server with 512 RAM, but with 20 GB SSD, of which 10 exactly under the pictures will remain).
True, for this you have to write such a server. Maybe there are ready-made solutions for such a task? I would look at the decisions both under Linux (based on NGINX, PHP, etc.) and under Windows (ASP.NET, ASP.NET CORE)
No special requirements, except that I would like to open to finish if that.
In general, the most convenient and advanced system in this plan is WordPress. There is everything here: a comfortable panel, an intuitive interface for ordinary users … But it is unlikely that someone will use such a bullfin only to load images =)
In essence, there is no finished engine, but there are some libraries and hubr! In This post is a small handler code. Of course, it is far from perfect: you need to finish the appearance, as well as resolve the issue of downloading images with the same names. But this is not a problem, right? In this case, you can use the current date / time with an accuracy of milliseconds just to generate a file name …