sass: retina-background-image

mixin_retina-background-image.scss

@mixin image-2x($image, $width, $height) {
	@media (min--moz-device-pixel-ratio: 1.3),
		 (-o-min-device-pixel-ratio: 2.6/2),
		 (-webkit-min-device-pixel-ratio: 1.3),
		 (min-device-pixel-ratio: 1.3),
		 (min-resolution: 1.3dppx) {
		/* on retina, use image that's scaled by 2 */
		background-image: url($image);
		background-size: $width $height;
	}
}

// div.logo {
//    background: url("logo.png") no-repeat;
//    @include image-2x("logo2x.png", 100px, 25px);
// }