Multiuser support is free, face detection is cheap enough embedded camera chips do it, metadata indexing is cheap with any recent DB engine, search is cheap with them as well.
The only computationally expensive thing here is face matching. Photoprism recommends two cores and 3G RAM and claims to be able to run on a NAS.
The only computationally expensive thing here is face matching. Photoprism recommends two cores and 3G RAM and claims to be able to run on a NAS.