On most modern Android devices you can change the screensaver for the device inside the device’s display settings. The screensaver can be set to the app and the settings can control whether one or more albums are included in the slideshow. The screensaver can be set to run when your device is idle, charging or docked.
If you are using an Amazon Fire TV, the steps to change the screensaver are more involved. Please see how to change the Fire TV screensaver for more information.