Ok .... so the way to get your photo albums to stay up on Apple TV is to use the home sharing version of the method;
switch off the default screensaver - DO NOT LET IT START BY SELECTING “NEVER START” from the Apple screensaver menu
select the PC / computer icon on the Apple TV.
find the photos and let them all start to display in thumb nails.
when most of the selected album is thumb nailed select the photos as the screensaver.
leave the source file open for at least 30 minutes depending on size of file being transferred.
after a length of time sufficient
preview the chosen screensaver to ensure it works as selected.
( I use cascade and have about 50,000 photos)
tune the Apple TV to never turn off.
done