I created an ad for a billboard and sidekick using those dimensions. The premise is a sci-fi film where an alien invasion takes place. Simple approach was taken I added both images and used a multiply filter on the alien image. I then used the gradient tool to create a pass-through effect.

Link to images used: http://www.wallpaperawesome.com/wallpapers-awesome/wallpapers-planets-stars-galaxies-nebulae-sci-fi-awesome/wallpaper-planet-collision.jpg

https://media3.s-nbcnews.com/j/newscms/2017_06/1894401/170207-aliens-rhk-1646p_05f77e2a819f9087a06bbdcf56776fb3.nbcnews-fp-1200-800.jpg