What does "referenced" mean in a smart album rule?

Any suggestions on how to identify photos that have not been added to an album?

You can find photos that have not been added to a standard album with a smart album based on the rule

"Albums is not Any".

"referenced" images in Photos are photos, that have not been copied into the Photos Library, but are referenced by Photos in their original location. This method should only be used, if your Photos Library is so large, that it does not fit onto the drive and you need to store the original images on a separate drive to save storage on the drive with the library. If you use this method to store the original image files outside the library, you cannot sync the photos with iCloud Photo Library, iCloud Photo Library only will work with managed originals. This page in the user guide explains referenced photos - see the link:

Change where Photos stores your files on Mac - Apple Support

BTW, you can use the keywords you assigned in Photos on your Mac to search for the photos on your iPhone or iPad. smart albums are unfortunately not supported by iOS, but if a photo has a keyword, you can type the keyword into the search field and Photos will find it on your iPhone.

referenced means that you did not copy the photo to the Photos library when you imported it but referenced it in its original location (which is a very bad idea BTW -- :Disadvantages of a Referenced Library in Photos )

to identify photos not in any album make a new smart album (file menu ==> new smart album) for -- Album - is not - any

LN

My library lives in iCloud.

not really - iCloud is not an off site storage service and nothing "lives" there - it is a syncing service that keeps multiple devices in sync so that all changes made on any device are made on all devices

and this is NOT the place to address Apple or tell them what you want - do that here - Product Feedback - Apple

LN

Understood. I'm still allowed to express a simple opinion though, am I not?

not really - this is an Apple forum subject to Apple rules as you agreed to and they forbid speculation on Apple policies amoung other things

LN

FWIW, I have submitted an RFE through the appropriate channel with each disappointing major release of the Photos app, as have dozens or hundreds of others based on other threads in this forum. Not that it has made a lot of difference, of course.

I am more optimistic.

Photos has become much more useable since the first release photos 1.0. Remember? In Photos 1.0 we could not batch change titles, sort albums, add locations to photos.

Hmm. I don't recall speculating on anything, I just stated an opinion.

Apple encourages us to post constructive feedback in these forums. Feature request and pointing out problems are perfectly within the Terms of Use (https://discussions.apple.com/docs/DOC-5952), see paragraph 2.3:

Post constructive comments and questions. Unless otherwise noted, your Submission should either be a technical support question or a technical support answer. Constructive feedback about product features is welcome as well. If your Submission contains the phrase "I'm sorry for the rant, but…" you are likely in violation of this policy.

Let's hope for iOS 12 to make things easier. The preview (https://www.apple.com/lae/ios/ios-12-preview/) announces smarter search tools in iOS 12 (but still no smart albums).

<soapbox> And Apple should be ashamed. </soapbox>

LN