I don't use iCloud. It is turned off. Photo synchronisation with iTunes on my Windows 10 PC is extremely slow, seeming to take way longer than I can wait. I don't think the photos have been copied across for months now, which may be part of the problem. Why is it so slow?
iPhone 8, iOS 11.2.6
iTunes will create a photo cache to speed up the syncing. The reason for this is, that iTunes is syncing the photos in reduced size to your devices. The first time you sync new photos, the syncing will be slow. If you sync the same photos again, it will be faster. If you use applications, that clean caches the next sync may be slow again, because the cache has to be recreated. Or if you just imported many new photos. See the last paragraph: About Photo Cache folders - Apple Support
The Photo cache folders may be needing lots of extra storage. Do you have enough free storage?
I'm not clear how the Photos Application or Mac is involved in your situation - this is the forum for Photos for Mac - there is a forum for iCloud for teh PC which may be where you want to post
LN
Photo synching with iTunes extremely slow
