How to set one photo as your Apple TV screensaver
There are several old questions about this with no solution. Here's what worked for me after randomly trying different screen saver transitions.
ATV is my shared album containing one image.
Remainder of my settings:
Screen Saver > Memories & Slideshows >
Your Photos > Albums > ATV
Transition > Style > Classic > Wipe
When I scroll back up and hit preview, the image remains static on the screen, with zero transition. Same after pausing a program for 2 minutes: the image displays continually with no transition.
I hope this works for others.
Apple TV 4K (3rd generation)