hiDPI mixin for passing content blocks into hi-rez media queries

hiDPI Mixin

/**
 * hiDPI Mixin
 *
 * http://css-tricks.com/snippets/css/retina-display-media-query/
 *
 * $resolution: 1.25, 1.3, 1.5, 2;
 */

@mixin img-rez($resolution) {
  @if $resolution == 1.25 {
    @media 
        (-webkit-min-device-pixel-ratio: 1.25), 
        (min-resolution: 120dpi){ 
        /* 1.25 rez specific stuff here */
        @content;
    }
  }
  @if $resolution == 1.3 {
    @media 
        (-webkit-min-device-pixel-ratio: 1.3), 
        (min-resolution: 124.8dpi){ 
        /* 1.3 rez specific stuff here */
        @content;
    }
  }
  @if $resolution == 1.5 {
    @media 
        (-webkit-min-device-pixel-ratio: 1.5), 
        (min-resolution: 144dpi){ 
        /* 1.5 rez specific stuff here */
        @content;
    }
  }
  @if $resolution == 2 {
    @media 
        (-webkit-min-device-pixel-ratio: 2), 
        (min-resolution: 192dpi) { 
        /* 2x rez specific stuff here */
        @content;
    }
  }
}