Synology Moments, replaced Google fotos in my Android phone. On my Sailfish OS phone, rsync to a personal cloud. My computer, Synching to local and cloud.
You don't have to. Just create a Nexcloud instance in cloud or local storage and you are set. I bought my Synology NAS just to add an extra layer of backup of my data. Which is three fold backed up
Of course you can. Be aware of Drive storage limits and data mining or the lack of privacy. Just for backups, it's another story.
I use multiple hard drives to store multiple copies. One backup of what is most precious to you is not enough. Dont trust cloud anything, especially if they need to be kept private.
Yeah but cloud is bringing easy use on phone, tablet, pc. Plus we can see pictures on map which we traveled. Synology is expensive, HDD breakable and only watch photos on pc.
Your question was You didnt ask what is the easiest way to view photos. 2 entirely difference topics with possibly different solutions.
As a certified technician, I can assure you that data recovery is expensive, backup is relatively cheaper.
Beside the internal storage ssd i have two 2tb cold storage usb hdds. Every now and then i plug them in make new backups of that ssd.
Last time i bought a new phone i chose pixel. Camera app and free google photo storage was the deciding factor. So i use full quality google photo and my old family photos got a local copy on my plex server.