Ah okay, I’m fairly out of my depth now. I don’t really know the costs of that amount of online storage. As long as you never lose your login details an online one is going to be safest.
iCloud is apparently
United States4 (USD)
50 GB : $0.99
200 GB : $2.99
2 TB : $9.99
So if you’re already at 80GB I’m confused how you’re running out of space since you must be on the 200GB level of $3 a month? Or is that because you have all your machine backups on there already.
Looking at Dropbox they seem to leap from 2GB free to 2TB with no in between but it seems slightly more than Apple for the same size.
I think also it sounds like you’re using Apple Photos which I never really understood, and which even Mac-Heads told me was utter shit. Like it sounds as if by saying you’ve moved the library you’re really talking about the index for the photos but they’re all still stored in whatever weird medium Apple uses.
In my head a photo library is just folders and folders of photos. I think what you’ve done (if that’s the case) sounds a bit unwise. Where are you planning for the 80GB of photos to eventually end up? If the endgame is actually to just have them on three different hard drives so one can sit in a safe, preferably remotely, and the other two in different places at home that makes sense. If you need them available outside your house you could probably get yourself a NAS with storage and put some TB drives in it and then open stuff out via the web, although compared to the costs of online storage you may find this will take you about 2 years before its profitable.