title: Remove custom background from ImageIcon
body: <p>As the title says, how can I do to remove the background from an imageIcon?</p>
  
  <p>Let's say.. I've a <code>JTree</code> (but it can be every <code>JComponent</code>) and I would like to set an icon for its leaf nodes.</p>
  
  <pre><code>myDefaultTreeCellRendere.setLeafIcon(new ImageIcon(icon));
  </code></pre>
  
  <p>The icon has the white background and I would like removing that. Is that possible?
  I read some answers on Stackoverflow but there a <code>BufferedImage</code> is used and the icon is retrieved from the web and stored in an URL object... My icon is local, instead. </p>