Bunch of tweaks and fixes.

example/example.js

@@ -1,16 +1,17 @@
+/*eslint no-console: ["error", { allow: ["log", "error"] }] */
 /**
  * Copyright (c) 2019-present Tomek Wójcik <contact@bthlabs.pl>
- * 
+ *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
- * 
+ *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
- * 
+ *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,7 +23,8 @@
 
 const {spritemaker} = require('../lib/spritemaker.js');
 
-spritemaker({
+console.log(spritemaker({
   files: ['./icons/*.png'],
-  output: './output/'
-});
+  output: './output/',
+  urlPrefix: '../img'
+}));