Some time ago I used Safe Camera to take sensible photos and share the encrypted files. As the app did not receive updates anymore, I had a look at the successor Stingle Photos which stores the encrypted files in the cloud. However, this would require me to trust their server. Luckily, they opensourced their code and some guys modified the app to use a self hosted server.
Using Community Applications/Docker:
https://github.com/n00b42/unraid-docker-templates to the list of template repositories.