iCloud Photos Shared Albums on Windows PC - terrible UI and bad perfomance
The iCloud photo upload to shared albums is abysmal in its UI and performance. The Explorer add-on is slow to respond, and often hangs (I have the latest version as of 8/7/2017). The shared album seems to remain blank if you upload several hundred pictures, until it is complete, assuming it completes at all. There is no visual indication of the upload happening, and you are left guessing until the end.
Lack of subfolder support is also annoying, as is the fact that you can't simply pick a photos album (already stored in the cloud) and say "share it". I bought 200G of space hoping this would be easy to use and work well. It isn't. If this is a strategy to make people switch to using a Mac then it is unlikely to work, and I hope that isn't the case.
I can see from my iPhone that pictures are being uploaded. Here is what I see in Windows Explorer:
Windows 10, iCloud Shared Albums in Explorer