Using iCloud as a back up location
I have a back up folder of photos on One Drive, the photos are already in my Icloud photos account so can me viewed from my iPad, Mac etc, this folder is purely a secondary back up file.
I want to close my One Drive account and make use of the additional storage space on my iCloud subscription. When I copied the back up folder from One Drive to iCloud, it also copied the files to my Mac SSD. When I tried to optimise the storage it seems the default position is to assume that I want to include all these pictures in iPhoto, which if I did, would import them into IPhoto again and therefore duplicate all of them (approximately 20K pictures).
I can't see an obvious way of telling iCloud not to sync a specific folder, i.e keep it in iCloud without downloading the entire folder to my MAC. Am I missing something obvious? I do have copies of the photo backup up on a external hard drive but want a cloud based back up too.
Can I use iCloud like I can with my One Drive account or is that asking too much?
Mac Pro