HOW TO Use iCloud Photos
1 Enable iCloud Photos in macOS
Like other iCloud features, iCloud Photos is now activated in System Preferences > Apple ID > iCloud. But all you can do here is turn it on or off. Open the Photos app and go to Photos > Preferences > iCloud for more options.
2 End of the Stream
The option (pictured here in macOS High Sierra) for My Photo Stream has gone in Catalina. Apple is phasing out this alternative system, which synced just your last 30 days of photos, up to 1,000 shots, outside your iCloud storage.
3 Download or optimise?
Select Download Originals to save full-res photos from all your iCloud devices on your Mac. Or if you don’t want to use all that space, select Optimise Mac Storage. Either way, deleting a photo in the Photos app deletes it in iCloud.
4 Enable iCloud Photos in iOS
In Settings, tap your name, iCloud, then Photos. All the sync options are here. While iCloud Drive always uses storage optimisation in iOS, with Photos you can keep full copies of everything – if your device has enough storage.
5 My Photo Stream
If you see an Upload to My Photo Stream switch, you can use this to see recent photos across all your iOS devices – handy if you’re shunning iCloud Photos to avoid paying for storage. Using both is kind of pointless, but possible.
6 Alternative clouds
You can use third-party photo cloud apps as well as or instead of iCloud Photos. In Google Photos, you can opt to back up either unlimited lower-res photos or originals up to your Google Drive storage limit (15GB is free).