I have 150GB of photos on my iPhone that were properly synced & backed-up with iCloud (full resolution).
I logged out of iCloud on my iPhone and have now logged back in again. I still have all my photos in my Photo app, but the iCloud sync is now turned OFF. When i try to turn it on, the OS complains that I only have 50GB space left on my iCloud storage and cannot backup my photos.
This seems to be a bug, it should indeed "know" that my photos are already backed up. But instead it seems to want to re-upload all my images (duplicate them?). How can I avoid this and turn iCloud backup for photos back on?