The most often it is scrnsave.scr (you can make a slideshow screen saver using GPO)
Screen saver timeout – sets time in seconds when a screen saver will be enabled and a computer will be locked if a user is inactive.Password protect the screen saver - prompts to enter a password to unlock a computer.There are some options to manage screen saver and screen lock settings in the GPO section:.Edit the policy edit and go to the User Configuration -> Policies -> Administrative Templates -> Control Panel -> Personalization.Open the Group Policy Management console ( gpmc.msc), create a new GPO object ( LockScreenPolicy) and link it to the domain root (or to the Users OU).Let’s create and configure a domain Group Policy to manage screen lock options:
