Important: backup apps and web galleries are different
Immich and Ente are backup-and-sync apps with mobile clients that upload your photos automatically, which is the closest to Apple Photos. Lychee and Piwigo are web galleries for organizing and sharing photos you add through a browser or import tools, and they are less suited to automatic phone backup.
Closest to Apple Photos
Immich is the closest, with automatic phone backup, face recognition, smart search, a map view, and RAW support, though it is self-hosted only. Ente focuses on end-to-end encryption: your photos are encrypted on your device before upload, and it can be used as a paid hosted service or self-hosted.
Self-hosting and cost
Immich has no official hosted service, so you run it on your own server and are responsible for backups. Ente Photos is a paid service with a small free storage tier, and you can also clone the repository and self-host. Lychee and Piwigo are lightweight to host, and Piwigo also offers managed hosting.
License details
Immich and Ente are AGPL-3.0, Lychee is MIT, and Piwigo is GPL-2.0. Lychee also offers a paid Supporter Edition with additional features.
Backups and safety
A self-hosted photo server is not a backup by itself. Keep a second copy of your library on separate storage, and test restores, especially with fast-moving projects such as Immich.
Maintenance status
All four projects were updated within days of this update.