Using Vector Assets in iOS 8
With iOS 8, you now have the ability to utilise vector assets in your applications, in place of bitmap images, which we traditionally used to work with. Using vector images allow us to satisfy multiple asset resolutions, which is pivotal when we have to deal with iPhone 5s, iPhone 6 and iPhone 6 Plus, saving you time and making your app more future-proof. It allows for graceful scaling of images.
There are some caveats of course, but to find out how to work with vector images, read What's Our Vector, Victor article, by the Big Nerd Ranch.