Expression coined by WRC-TV (Washington DC) meteorologist Tom Keirien to describe a sunrise so impeccably perfect that words are inadequate; the only tribute to do it justice would be to freeze-frame and fly the image into a computer to use as desktop artwork.
Use of the term "screensaver" might be considered inaccurate were the image to be used for the Desktop or as Wallpaper instead of as a screensaver. But in context the usage is acceptable, as everyone gets it.
Newshosts - What's the weather like, Tom?
Tom - Take a look at our City Camera at this screensaver sunrise.