Sync windows folders with iCloud Photo Library

I've spent many years building up a library 350 GB of photos and videos on my windows PC (Windows 7), somewhat meticulously organized into folders.

I'd like to share these via the iCloud Photo Library with my various apple devices. Then set up my iPad as a digital picture frame that would shuffle through the whole library at random.

However, I'm not really sure of what the easiest path is for doing this. Does anybody have any suggestions for how this could be accomplished? If it can't be done via the iCloud Photo Library, then any other apps or methods would also be appreciated.