Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.0.rc.1)
// Compass (v0.13.alpha.10)
// ----

@import "compass";

// Retina Wrapper
// Wrap anything in a resolution query
//
// Params:
//   $background-size - Optional value to set background size
//
@mixin hdpi-wrapper($background-size: FALSE) {
  @media only screen and (-webkit-min-device-pixel-ratio: 2),
  only screen and (min--moz-device-pixel-ratio: 2),
  only screen and (-o-min-device-pixel-ratio: 2 / 1),
  only screen and (min-device-pixel-ratio: 2),
  only screen and (min-resolution: 192dpi),
  only screen and (min-resolution: 2dppx) {
    @content;
    @if $background-size != FALSE {
      @include background-size($background-size);
    }
  }
}

.retina-magic {
  background: image-url('test-1360×572.jpg') no-repeat 0 0;
  @include hdpi-wrapper(1360px 572px) {
    background: image-url('test-2720×1144.jpg') no-repeat 0 0;
 }
}

SassMeister-output.css

@charset "UTF-8";
.retina-magic {
  background: url('/test-1360×572.jpg') no-repeat 0 0;
}
@media only screen and (-webkit-min-device-pixel-ratio: 2), only screen and (min--moz-device-pixel-ratio: 2), only screen and (-o-min-device-pixel-ratio: 2 / 1), only screen and (min-device-pixel-ratio: 2), only screen and (min-resolution: 192dpi), only screen and (min-resolution: 2dppx) {
  .retina-magic {
    background: url('/test-2720×1144.jpg') no-repeat 0 0;
    -moz-background-size: 1360px 572px;
    -o-background-size: 1360px 572px;
    -webkit-background-size: 1360px 572px;
    background-size: 1360px 572px;
  }
}