Compass Sprites with Retina support

style.scss

// Only requirement: save all your .png files in 2x format. As this uses background-size, only IE9+ supported, but will look nice for both retina and non retina devices.
// Just because I like to use <span>s
.icon-sprite {
    display: inline-block;
}
// Compass automagically generate sprites
@import 'icon/*.png';
// Override the mixin Compass core uses to generate the width/height/position and include background-size
@mixin sprite-background-position($map, $sprite, $offset-x, $offset-y, $fifth) {
    $ypos: round(nth(sprite-position($map, $sprite), 2) / 2);
    $width: image-width(sprite-path($map)) / 2;
    $height: image-height(sprite-path($map)) / 2;
    background-position: 0 $ypos;
    background-size: $width $height;
    height: sprite-height($map, $sprite) / 2 !important;
    width: sprite-width($map, $sprite) / 2 !important;
}
// Print out all the classes, ready to go!
@include all-icon-sprites;

HA! me acabo de dar cuenta que eres Tommy from block ;)