Originally Posted by ryck
Originally Posted by joemikeb
Given the size of your photo Library, I strongly urge you to re-think your decision and pay for the extra iCloud capacity.
I've done that (50GB) but now have two new issues as I thought, given all that capacity, I should link my iPhone and my iPad to iCloud.

First the iPad. I tried to turn on iCloud Photo Library and got a dialogue box that cautions:

“Photos synced from iTunes will be removed. Syncing photos via iTunes is not supported when iCloud Photo Library is turned on. 203 photos will be removed.”

Synched from iTunes? I haven't a clue what that means. I don't even know which the 203 photos would be.

Plug your iPhone into your Mac, and assuming you are on a recent version of macOS and iOS the iPad will appear in the Finder sidebar under “Locations”. Select the phone and follow the on-screen instructions to sync your iPad. This will result in the 203 photos being added to the Photos library on your Mac and from there on iCloud. Repeat this with your iPhone. Note you may see extra battery drain for a day or two while the images are appropriately optimized for each device. At the end of this process, all of your devices will automatically share the same Photo Library.

As a "belt and suspenders" step, be sure and backup each of the devices once you have them all synchronized. FWIW I backup my iPhone and iPad to iCloud almost every night.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein