"Photos": Photo Sharing with iPhone???

My Photostream was a syncing system that is giving way to iCloud syncing. iCloud syncing transfers pictures from the to the "Cloud" and then from the Cloud to the Mac, back and forth. You can go to iCloud.com from any browser anywhere and see all your pictures, and all your devices keep in sync pretty much effortlessly. If you have lots of pictures, you would need to pay Apple a bit for the storage space in iCloud ,like $3/month for 200GB. It's pretty cool.

So, check iCloud.

Set up and use iCloud Photos - Apple Support

Optimize Storage means that only smaller, screen-sized images may be stored on you Mac (and a similar setting for the phone). The pictures look as good as they can look on the screen, and when you want to edit or print them, the computer brings them in for full resolution. You usually have to be connected to the internet to edit or print. I have plenty of room on my Mac's hard drive, so I don't check this. That way, when I back up my Mac, I'm backing up full sized images. Of course, the full sized images are alway in iCloud.I do have it checked on my phone.

Shared Albums lets you make pictures available for friends and relatives who use Mac Photos. If your interested, you can look here:

How to use Shared Albums in Photos on your iPhone, iPad, and Mac - Apple Support

Hi CharPatton,

The service you're looking for is iCloud Photos, which will sync your Photos libraries across all of your Apple devices signed in and using that feature via iCloud. Set up and use iCloud Photos offers the steps to enable this service for iPhone, iPad and Mac as:

"On your iPhone, iPad, or iPod touch

1. Go to Settings > [your name].
2. Tap iCloud.
3. Tap Photos, then turn on iCloud Photos.

On your Mac

1. Choose Apple menu  > System Settings or choose Apple menu  > System Preferences.
2. Click Apple ID. 
3. Click iCloud in the sidebar, then select Photos."

Regards.

Good afternoon CharPatton,

It might be helpful for you to speak directly with an Apple advisor about this issue. Click the link below, choose the phone number for your region from the list, and call when it is convenient.

Contact Apple for support and service

They will look into the format error you are seeing with your Mac Studio.

Take care.

You may also want to click the first tab in the Photos Preferences - Photos > Preferences > General.

Make sure, that "Use as System Photos Library" is enabled. If this button is not dimmed, click it, to make the currently open Photos Library your System Photos Library. Then you should be able to enable iCloud Photos. Only the System Photos Library can be made your iCloud Photos Library.

Also look at the line "Library Location" at the top of the "general" tab. It shows you, where your currently open Library is located. The best place would be the Pictures folder in your user home folder.

The error message you have shown suggests, that Photos is currently using a library on an external volume, with a different file system format, not a library on your internal drive.

Have you turned on iCloud by going to Preferences>iCloud in the Photos app? This isn't a system setting, it specific to the Photos app.