scss background-image: url() mixin

_bg-url.scss

@mixin bg-url($url, $url2x: false, $webp1x: false, $webp2x: false) {
  background-image: url($url);
  @if $webp1x {
    .webp & {
      background-image: url($webp1x);
    }
  }
  @if $url2x {
    @media
    screen and (-webkit-min-device-pixel-ratio: 2),
    screen and (min-resolution: 192dpi),
    screen and (min-resolution: 2dppx) {
      background-image: url($url2x);
      @if $webp2x {
        .webp & {
          background-image: url($webp2x);
        }
      }
    }
  }
}