iPhone 15 Pro: Full Photo Library Access only 51 photos

I haven't got Whatsapp, so I can't test it. If I try the Messages and Mail apps on my iPhone and add a photo then I can select any photo, including the ones synched with My Mac. Note that my privacy settings are the same as yours. It says I've only got 117 pics - which are the ones I've taken with my phone - but I have about 10k in the From My Mac folder which Messages and Mail can see OK.

Sorry I can't give a definitive answer but this might be a Whatsapp limitation rather than Photos. Have you checked the Whatsapp Privacy settings.

I'm not an expert in this so maybe later as more folks come online you might get a better answer, but here goes. I see the same thing - although I've never looked at this before. Like you (I assume) I manage all my pics on the Mac and synch them with the iPhone so they appear in the Photos library in the "From My Mac" folder. The only pics in the Photos app on the phone are ones I've taken with the phone or transferred in to use as screen backgrounds. I think that Photos only considers items which are inside the photos app as photos, hence that's what you see in the Privacy settings.

Why is it a problem? Are the privacy settings preventing you from doing something you need to do with pics in the From My Mac folder? If so then that might be a better question to ask.