About wallpaper app for iPhone Duo

I'm building a wallpaper app for iPhone Duo. The outer display is portrait (1398×2034), and the unfolded inner display is landscape (2670×1878). My wallpapers are portrait images — for example, a person centered in the frame. When the user unfolds the device and the screen changes from portrait to landscape, how does iOS adapt the wallpaper? Specifically: Does it crop a landscape region from the portrait image (which could cut off the subject)? Does it preserve the focal point the user chose when setting the wallpaper, keeping the subject in frame? Or can separate images be assigned to the outer and inner displays? I need to understand this behavior to decide what compositions to offer in my app.