background: -webkit-image-set(url(image.png) 1x, url
}It's really important to define background the traditional way, because not every webbrowser recognize -webkit-image-set function.
To work with retina images more productively, it's good to use a tool to resize images automatically. I recommend Sizes app, because it alows you to use different suffix (like _2x) instead of @2x and makes image resizing really simple.
More details you can find in Safari Development Library.