Having a MacBook and iPhone I use iCloud to store photos and synchronise them between the two devices. In general this all works well but sometimes it can be very infuriating, in particular it sometimes gets fed up and decides not to synchronise photos. In such times one really misses a large button marked ‘force synchronisation’ or similar but unprintable phrases.
Looking around the web throws up such comments like the photos app will not pull new photos down from iCloud until it has finished uploading. Ok I can see the logic there and presumably there is some form of contention checking, for example if a photo was edited on both devices simultaneously.
But when it fails to update it is really frustrating!
I had this recently where I had taken a lot of photos of documents on the iPhone and later adjusted these on the Mac to put them the right way up. After that, no sync. Nothing. Several days later and no amount of fiddling or swearing made any difference. So I wondered if it was simply never finishing uploading the changes. Tethering the Mac to the phone so it uses 4G made no difference.
What appears to solve it was I selected all the changed photos on the Mac and reverted them to the originals, all of which were taken on the phone. My assumption here was that the originals are on the phone and had synchronised to iCloud and later arrived on the Mac but the changes made had clogged the thing up.
Low and behold about 10 minutes later and all new iPhone photos have arrived on the Mac and everything is in sync again. While this is not really a solution it does mean I need to be careful bulk-modifying photos. Rather annoying really but hey.