iOS full screen background image for all screen sizes

Question

I'm trying to set a background image for my app that will scale to fill the 4, 4.7, and 5.5 inch screens.

• I'm working in XCode 6 with swift
• I created a 640 x 1136 image, and pasted @1x, @2x, and @3x images in my images.xcasetts folder. I selected the 'scale to fill' mode for the image view.
• I created a UIImage in the main.storyboard file for the 4 inch screen. This image fills the screen just fine when I build.
• I think I've tried just about every combination of height / width / aspect ratio constraints with no luck.

Answer 1

The 4 and 4.7 use @2x, 5.5 used @3x, please see the screenshot detail.

You can download the PDF that is the origin of this screenshot from Ugur Akdemir's Dribble.