How to set the same wallpaper on 2 iPhones like say the left side was one phone n the right pic is the other phone?

Please help

Crop the photo in a photo editor so you have one half and they have the other. Simple

Use the same image on both. Move 1 to the left, move 1 to the right. Done. (Assuming the picture has a higher resolution than the iPhones' (didn't mention which phones) display.