A comparison of `else` placements in a SCSS mixin.

_retina-images.scss

// Bourbon _retina-images.scss via:
// https://raw.githubusercontent.com/thoughtbot/bourbon/502c2108dea1970ffeb4f91cb95b545d67bddfd0/app/assets/stylesheets/addons/_retina-image.scss

// Current version with @else on a new line
@mixin retina-image($filename, $background-size, $extension: png, $retina-filename: null, $retina-suffix: _2x, $asset-pipeline: $asset-pipeline) {
  @if $asset-pipeline {
    background-image: image-url("#{$filename}.#{$extension}");
  }
  @else {
    background-image:       url("#{$filename}.#{$extension}");
  }

  @include hidpi {
    @if $asset-pipeline {
      @if $retina-filename {
        background-image: image-url("#{$retina-filename}.#{$extension}");
      }
      @else {
        background-image: image-url("#{$filename}#{$retina-suffix}.#{$extension}");
      }
    }

    @else {
      @if $retina-filename {
        background-image: url("#{$retina-filename}.#{$extension}");
      }
      @else {
        background-image: url("#{$filename}#{$retina-suffix}.#{$extension}");
      }
    }

    background-size: $background-size;

  }
}

// Updated version with SCSS Lint `ElsePlacement`, `same_line` setting respected
@mixin retina-image($filename, $background-size, $extension: png, $retina-filename: null, $retina-suffix: _2x, $asset-pipeline: $asset-pipeline) {
  @if $asset-pipeline {
    background-image: image-url("#{$filename}.#{$extension}");
  } @else {
    background-image:       url("#{$filename}.#{$extension}");
  }

  @include hidpi {
    @if $asset-pipeline {
      @if $retina-filename {
        background-image: image-url("#{$retina-filename}.#{$extension}");
      } @else {
        background-image: image-url("#{$filename}#{$retina-suffix}.#{$extension}");
      }
    } @else {
      @if $retina-filename {
        background-image: url("#{$retina-filename}.#{$extension}");
      } @else {
        background-image: url("#{$filename}#{$retina-suffix}.#{$extension}");
      }
    }

    background-size: $background-size;

  }
}