Sass & Compass sprites for standard and HD displays

gistfile1.scss

// Sprite mappers
$sprite:    sprite-map('sprite/standard/*.png', $layout: 'smart');
$sprite-hd: sprite-map('sprite/hd/*.png', $layout: 'smart');

// HD media query
$hd:        'print, (-o-min-device-pixel-ratio: 5/4), (-webkit-min-device-pixel-ratio: 1.25), (min-resolution: 120dpi)';

// HD mixin sprite
// Your HD files should necessarily be twice the size of the standard ones
@mixin hd-sprite {
    @media #{$hd} {
        background-image: $sprite-hd;
        background-size: image-width(sprite-path($sprite-hd))/2 image-height(sprite-path($sprite-hd))/2;
    }
}

// Usage
.some-logo {
    @include sprite($sprite, some-logo, true);
    @include hide-text(left);
    background-image: $sprite;
    @include hd-sprite;
}