Nextcloud

photOS snychronizes images from a WebDAV server. Although any standard compliant server should work, this page explains a setup using Nextcloud. With Nextcloud and the corresponding smartphone app it is possible to send photos directly from your smartphone to your photo frame. In addition, it is very simple to give other Nextcloud users permissions to also add images to your photo frame.

It is advised to create a separate Nextcloud user (e.g. photoframe), as the password needs to be stored in cleartext on that device and gives access to all data on that account. As user photoframe create a folder "photos" and share the folder with your main Nextcloud account and additional accounts or gropus (family, friends, flatmates, ...). All those accounts can now share images with your photo frame.

The WebDAV URL needed for configuring photOS is typically something like https://your.nextcloud/remote.php/dav/files/photoframe/photos.