title: Background image for a jPanel not working
body: <p>I am new to making GUIs so I decided to try the the windows builder for eclipse, and while great I do have some doubts. I have been searching but I cannot seen to find a good way to add a background image to my "menu". For example I tried this:</p>
  
  <pre><code>public Menu() {
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setBounds(50, 50, 300, 250); //Dimensiones
  
  contentPane = new JPanel() {  //Imagen de Fondo
  
      public void paintComponent(Graphics g) {  
            Image img = Toolkit.getDefaultToolkit().getImage(  
            Menu.class.getResource("/imgs/rotom.jpg"));  
            g.drawImage(img, 0, 0, this.getWidth(), this.getHeight(), this);  
          }  
  };  
  </code></pre>
  
  <p>And adding the following classes:</p>
  
  <pre><code> import java.awt.Graphics;  
   import java.awt.Image;  
   import java.awt.Toolkit;  
  </code></pre>
  
  <p>But to no avail the window remains with its dull grey color, so far my code is just the standard one WindowsBuilder cooks for you plus 4 buttons but I doubt they're of importance here. Shouldn't the code I added override the paintComponent() method of the jPanel and draw the image in it?</p>
  
  <p>The class for the menu is in a package within my project and the image is within a imgs package is within the same project as well. </p>
  
  <p>Thanks a lot in advance.</p>