title: Background images and Images.xcassets
body: <p>In my xcode 6 project (built for iphone) and in my storyboard i have a imageView thats i want to cover the whole canvas that acts as a background image. I'm really struggling to get my head around the Images.xcassets, i have added a new image set and in the attributes inspector i have set devices to device specific, in the check box i have iPhone and Retina 4-Inch checked. My question is what size should my images be at 1x, 2x, Retina 4 2x and 3x to scale the whole background. I think my image sizes are correct but the image size for Retina 4 2x is really confusing me.</p>