When a static image displays for extended periods of time, you may see a faint remnant of that image even after a new image displays. This is called image retention.
To prevent image retention:
Set the display to turn off after a few minutes of idle time.
Rotate background images periodically.
Turn off the display when the device is not in use.
While the static image is active, use a screen saver with one or more of the following characteristics:
The background color is set to black.
A small moving image (approximately 2% of the display size).