_hdpi.sass

/// High-DPI background images
/// Image for high DPI must have a '@2x' suffix (e.g. 'funny-animal@2x.png')
///
/// @param {string} $url - URL of the image, without extension
/// @param {string} $ext ['png'] - extension, .png by default

=bg_hdpi($url, $ext: 'png')
  background-image: url("#{$url}.#{$ext}")
  background-repeat: no-repeat
  background-size: contain
  background-position: center
  @media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi)
    background-image: url("#{$url}@2x.#{$ext}")