If I turn on iCloud Photo library, does my local Photo library on my iMac still remain intact and still receive new photos and videos as well?

I was under the impression that my local Photos library on my iMac would always remain in-tact and updated independently of the iCloud Photo library. Is this not true?

It is provided you enable photo stream instead.

but it became unclear whether or not deleting my files on my phone would also result in them being deleted from the iCloud library as well.

With iCloud Photo Library enabled, you cannot delete a photo on one device (or at iCloud.com) without deleting it from every device that uses iCloud photo library (and iCloud.com). In order to save space on your mobile devices (and indeed your Mac if you wish to do so) turn on optimisation for photos on these devices (settings > photos & camera > optimise storage on your mobile device and Photo preferences > optimise storage on your Mac)

Optimisation is dynamic, it reduces the resolution of your photos as and when needed, so you may not notice it occurring at first. However when it is needed, it is very effective and users have reported libraries being optimised to much less than 10% of their original size in some cases. My own library is about 9% of its original size on my phone.

Hey FortunatoMedia,

That is possible if you have the iCloud Photo Lilbrary turned off on the iPhone. With it off the changes you make to Photos on your iPhone are kept separate from your iMac and iCloud Photos. Similarly, if you only turned off the iCloud Photo Library on your iMac, and left it enabled on your iPhone, the changes you make on your iPhone will effect the phone and iCloud Photos.

Since you're concerned about space on your iPhone I'd follow Winston Churchill's suggestion and leave the iCloud Photo Library off on the iPhone but leave Photostream on so pics and videos can still sync to your iMac. That way you are able remove stuff without it deleting on the iMac. I have a 16GB iPhone myself and I would occasionally get the same space error with the optimize storage option. If I had a phone with more storage it may not be an issue but I prefer this setup.

Yes, there is a danger of losing items if they are deleted from the phone. iCloud is a syncing system, not an external storage system.

FortunatoMedia wrote:

Thank you Mr. Apple.

So from your response I gather that my current configuration is safest for me. I have iCloud Photo Library turned off on my iPhone and also turned off on my iMac, but I do have Photostream turned on. So whenever I dock my iPhone and let it synchronize with my iMac, it loads my latest photos and videos to my iMac's Photo library.

Photo stream doesn't require you to 'Dock' your phone. Providing photo stream is enabled on both devices and they have a wifi connection, the photos in photo stream will sync over air.

except for the fact that only some of my shared folders re-populated, while others now site empty in Photos on my iMac.

Shared albums are another matter altogether, shared albums are controlled by the iCloud Photo sharing settings not iCloud photo library or photo stream settings

if anyone can just give me a "Yes" or "No" answer:

Assuming iCloud Photo Library is turned ON on both my iPhone and my iMac, is the Photo Library that is stored locally on my iMac merely COPIED to the iCloud and therefore never really in any danger of being overwritten or deleted from when photos and movies are deleted from my iPhone?

There isn't just a danger of a photo or video being deleted from your Mac if you delete it from your phone, if you have iCloud photo library enabled it will be deleted, that's exactly what it is supposed to do.

You are welcome.