I use iCloud Photo Library to sync my photos and videos between multiple devices (two Macs, iPhone, iPad). One of the Macs is set to keep all original files from the iCloud Photo Library. Everything is working fine, but the shown storage usage does not make any sense to me.
The Mac that's set to keep the originals has a "Masters" folder of roundabout 115 GB - that is, to my understanding, the raw image data and not counting for any significant metadata (smaller previews, faces information, etc.)
My iCloud dashboard shows that only 27 GB are in use for photos and videos - that is way less than expected. Most interestingly, I was able to re-download the library to my Mac with 115 GB of image masters from those 27 GB. That does not make any sense to me.
I'm worried that the iCloud storage usage counting is corrupted. As far as I can tell, no image data seems to be lost. Any explanation is highly appreciated.