I\'m using storyboards to layout my view controllers and I would like to use stretchable images for my buttons (so that I don\'t need to generate several images with differe
With Xcode 6 (and iOS7+ target) you can use slicing editor when working with images assets. Toggle slicing mode with Editor -> Show Slicing menu or press Show Slicing button when select specific image with editor (showed below).

Then you can select image for specific display scale and drag rules or edit insets values manually.

After that you can select this image in Interface Builder. For example I use it for UIButton Background Image (IB button's representation could look bad, but it should be OK when running).
My buttons look well (running iOS 7.1 simulator and iOS 8 device).

This Apple doc link could be helpful.