title: How to use iconutil on mac to generate icns file
body: <p>I have created a directory with the icon set extension and put some png file there.  After typing the below commands I have been unable to generating icon files. </p>
  
  <pre><code>$ mkdir myicon.iconset
  $ iconutil -c icns myicon.iconset
  $ Failed to generate ICNS.
  </code></pre>