Is it possible to sync a Photos library hosted on external HD with iCloud? I have a ~90 GB Photos library on an external hard drive. Every time I want to access those photos, I need to have access to and to connect this hard drive. I was thinking about syncing with iCloud so:


I can access a copy of the photos wherever I have an Internet connection.
I would also have an offsite backup.


My question: Is it merely a matter of going into System Preferences → iCloud → and ticking the Photos box? If it is, I’m guessing I must have the external hard drive (where the Photos library it) connected when I do it, and must be ready to leave it connected for a while (maybe overnight) while it syncs with iCloud?
Is it merely a matter of going into System Preferences → iCloud → and ticking the Photos box?


Yes.


  If it is, I’m guessing I must have the external hard drive (where the Photos library it) connected when I do it, and must be ready to leave it connected for a while (maybe overnight) while it syncs with iCloud?


Yes,