Animated screen savers are moving aesthetic images that are exhibited by the computer's program when the electronic device is on but no activity has been sensed from the user for a specified period of time. The program determines the halt of the user's activity by the absence of keystrokes or mouse movements in a certain time span.
The initial purpose of screen savers was to prevent damage to the monitor. In older computer displays, prolonged static images could literally burn into the screen which made animated screen savers very useful. They can also be password protected and can be used to decorate the screen.