Usually what you're doing in those cases is that part of the image are stretchable and other parts are fixed. It's a technic that's been used for rounded button

Usually what you're doing in those cases is that part of the image are stretchable and other parts are fixed. It's a technic that's been used for rounded buttons for ages, and can be applied to pretty much anything. That's also part of xcode (unless it's been removed). But generally, you can easily have those kinds of design work with any kind of screen dimensions. It won't look completely similar from one size to another, but still look realistic (bigger screen -> bigger objects, or more space between objects).