Deleting photos off iPhone, keeping on iMac
I've read a number of threads on this, but still am unsure of the behavior in Big Sur.
I keep a huge Photos library file on my local drive in Photos, with all of my pictures. This is what I want to maintain as the master storage of all my photographs.
I do not use iCloud for photos.
I DO use My Photo Stream to pull in 30 days of photos on other devices.
I have synced my phone photos to the Mac, and now have 4700 pictures I'd like to delete from the phone. Previous to Big Sur I would have used Image Capture to copy them (as a backup) and then delete them. That option seems to be gone.
How can I delete them just from my phone, while leaving them on my iMac?
Thank you for all help.