When you use scale outer, you must design your layout/background ect to cover more than what you expect a "normal" user to see.
When you use scale inner, you design for parts of your layout to be cut off when viewed by a different aspect ratio than expected.
Thank you for the answer.
I see, but do i make the layout size larger, or just the (sprite-background).
and how do i do that when using a scrolling backgroud?