Photos for Mac: HEIC and jpeg of the same picture
I'm using Photos for Mac: photos I take with my iPhone 7+ in HEIC format. They are sent to iCloud via My Photo Stream (I am not using the Photo Library) and I find them in Photos on the Mac. But when I afterwards synchronise pictures and video from my iPhone with the cable to the Mac, I'll end up with duplicates in JPEG and HEIC. This drains my memory. It started in September last year.
How do I solve this problem?
MacBook Pro with Retina display, macOS High Sierra (10.13.4)