Selfhosted would still be better but you can usr any instance of Lutim (Framapic for example) or img.bi because the picture is encrypted before upload. It's like ZeroBin and Privatebin.
There's Lutim (Let's Upload That Image) that might fit the bill for you. You can set it to encrypt the uploaded images.
Bonus point for you: yes, it has a Docker image, although installing it without Docker is quite easy :)
It's not exactly what you're looking for, but have a look at Lutim: https://framagit.org/fiat-tux/hat-softwares/lutim
There is also a "burn after reading" option and an auto delete time, but not less than 24h currently.