Understanding Apple TV Photo Cache on iTunes for Windows

I am displaying photos from my Windows PC iTunes to a television using a Gen 3 Apple TV 4k. Apparently iTunes builds a photo cache (in folder .../Apple TV Photo Cache/Apple TV Photo Database). Sometimes the Apple TV takes a long time to load my Photo Libraries because apparently iTunes is updating/building the photo cache. Can someone explain to me at a relatively high level (not looking for any trade secrets):

1. What is in the photo cache? I am assuming it contains some sort of pointers to the locations of the photos and possibly some metadata about each photo.
2. How often and/or when is a rebuild of the cache triggered?
3. I am assuming that iTunes builds the cache (since it is building it now and CPU usage is very high) and the Apple TV reads it when I want to display photos. Is this correct?

Thanks!

[Re-Titled by Moderator]