TV as digital signage

Hi,

We've got close to a couple dozen 3rd gen Apple TVs across all of our establishments that we use for digital signage. We use albums in Flickr as the source for the screensaver slideshow for each display. Flickr started off as kind of reliable, but has slowly degraded to the point where we must manually run the slideshows rather than just let them pick up new slides automatically.

Experimenting, we've found that shared iCloud albums are much more reliable, and will pick up a new slide within just a few minutes of it being added to the shared album. However, most of our users are Windows-based, and deploying the iCloud Control Panel and teaching already overworked staff how to put photos in the albums is probably out of scope of this project. It's not as easy as dragging and dropping a file into Flickr.

I've started looking into setting up a single centralized Windows system running iTunes and Home Sharing, with separate folders for each Apple TV. However, the Apple TVs are all connected via WiFi, all the PCs are on Ethernet, and the subnets are different -- preventing Home Sharing from working.

I've got one Apple Server, running 24x7. Does anyone know of a program that will allow Automator or AppleScript to pick up photos and put them into iCloud Photo Albums? (I don't think there's a published API for doing that, so I don't think it's do-able.)

Or, is anyone else using multiple Apple TVs as digital signage, and if so, how are you handling adding photos?

Thanks for any ideas,

Aaron