It was a feature my s7 edge had that would allow me to make a full image fit no matter the size but when you scroll from one screen to the other it shows the rest of the image
I think you need a launcher like Nova. Here's a video of it working on S6 Edge + https://www.youtube.com/watch?v=qCuqIr9VnDI
I have Nova on my S8+ and the same options are listed.