docs: function updateReferences(images, options, sprites, css) {
  	return new Promise(function (resolve) {
  		css.walkComments(function (comment) {
  			var rule, image, backgroundImage, backgroundPosition, backgroundSize;
  			// Manipulate only token comments
  			if (isToken(comment)) {
  				// Match from the path with the tokens comments
  				image = _.find(images, {path: comment.text});
  				if (image) {
  					// 2x check even dimensions.
  					if (image.ratio === 2 && (image.coordinates.width % 2 !== 0 || image.coordinates.height % 2 !== 0)) {
  						throw log(options.logLevel, 'lv1', ['Lazysprite:', colors.red(path.relative(process.cwd(), image.path)), '`2x` image should have' +
  						' even dimensions.']);
  					}
  
  					// 3x check dimensions.
  					if (image.ratio === 3 && (image.coordinates.width % 3 !== 0 || image.coordinates.height % 3 !== 0)) {
  						throw log(options.logLevel, 'lv1', ['Lazysprite:', colors.red(path.relative(process.cwd(), image.path)), '`3x` image should have' +
  						' correct dimensions.']);
  					}
  
  					// Generate correct ref to the sprite
  					image.spriteRef = path.relative(image.stylesheetRelative, image.spritePath);
  					image.spriteRef = image.spriteRef.split(path.sep).join('/');
  
  					backgroundImage = postcss.decl({
  						prop: 'background-image',
  						value: getBackgroundImageUrl(image)
  					});
  
  					backgroundPosition = postcss.decl({
  						prop: 'background-position',
  						value: getBackgroundPosition(image)
  					});
  
  					// Replace the comment and append necessary properties.
  					comment.replaceWith(backgroundImage);
  
  					// Output the dimensions (only with 1x)
  					if (options.outputDimensions && image.ratio === 1) {
  						['height', 'width'].forEach(function (prop) {
  							backgroundImage.after(
  								postcss.decl({
  									prop: prop,
  									value: (image.ratio > 1 ? image.coordinates[prop] / image.ratio : image.coordinates[prop]) + 'px'
  								})
  							);
  						});
  					}
  
  					backgroundImage.after(backgroundPosition);
  
  					if (image.ratio > 1) {
  						backgroundSize = postcss.decl({
  							prop: 'background-size',
  							value: getBackgroundSize(image)
  						});
  
  						backgroundPosition.after(backgroundSize);
  					}
  				}
  			}
  		});
  
  		resolve([images, options, sprites, css]);
  	});
  }