Hi, I had the same requirements as you (serve all images on a folder in a friendly way, read only). On first tests it works brilliantly. I found one usability issue:

When a video or photo is full-screen on a mobile device, the close button on the top right is invisible, and not clickable (or my aim is not good enough ;-) . On a desktop I hit the "Esc" key but on the phone I cannot do that.

Thanks for building this, it is very impressive, and fast! I'm running it as docker compose with local API server on a Mac Mini M1.