code: function mkSprite(srcFiles, destImage, options, callback) {
  		
  		options.src = srcFiles,
  
  		grunt.verbose.writeln('Options passed to Spritesmth:', JSON.stringify(options));
  
  		spritesmith(options, function(err, result) {
  			// If an error occurred, callback with it
  			if (err) {
  				grunt.fatal(err);
  				return;
  			}
  
  			// Otherwise, write out the result to destImg
  			var destDir = path.dirname(destImage);
  			grunt.file.mkdir(destDir);
  			fs.writeFileSync(destImage, result.image, 'binary');
  
  			grunt.log.writeln(destImage, 'created.');
  
  			callback(result.coordinates);
  		});
  	}
docs: Create an image from `srcFiles`, with name `destImage`, and pass coordinates to callback.