

That really depends on the software you use. Some software might have a way to do it, but it may be indirect.
E.g. digikam is a photo library management software. It can move albums between “libraries”, and is designed that some of those libraries can be offline occasionally (more in the sense of SD cards, but also e.g. USB storage). So how you could do it is you map one, mountable, library to one disk, another to your “network storage” (however you attach your home server). That includes the metadata (depending on where and how you store it). And the digikam database itself is just a file as well (sqlite database), so you can also back that up at the same time. I’m not sure how to automate this process. Even a manual “cheat” - moving the files to network drive, then symlinking it back, per month or something, might work. It’s a bit of a manual process, but digikam is designed to be storage-based. And a lot of other software is, as well.
But again, I don’t know if you’re using digiikam or something else, and how you set it up. So, what software do you have? How do your users sync their photos and albums? That might help planning.
Also, there was a comment on “arbitrary scoring for demo purposes”, but it’s still biased, based on biased dataset.
I guess this is just a bait prompt anyway. If you asked most politicians running your government, they’d probably also fail. I guess only people like a national statistics office might come close, and I’m sure if they’re any good, they’d say that the algo is based on “limited, and possibly not representative data” or something.