Problem with images

Hi!

I'm having a really frustrating problem with displaying images: the
problem is that when I created a GUI (using swing) the images doesn't
appears until I made the slightest change to the size of the window.

For the image, I'm using a JLabel with the setIcon() method.

I have tried all kinds of Layout Managers and all kind of combinations
of sizes for all elements (JFrame, JPanel's, JLabel's, etc) but
nothing seems to work.

Does somebody knows what may be happening?

Thank you very much!

This is my exact code:

public class InterfazCrucigrama extends JFrame {

    private JLabel panelImagen;

    public InterfazCrucigrama() {
       setTitle( "Crucigrama" );
           getContentPane( ).setLayout( new BorderLayout(10,10) );
           setSize( 800, 600 );
           setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
           setVisible(true);

           panelImagen = new JLabel("");
           panelImagen.setIcon(new ImageIcon("data/imagenes/
titulo.png"));
           getContentPane().add(panelImagen, BorderLayout.NORTH);
    }

    public static void main(String[] args) {
        InterfazCrucigrama miCrucigrama = new InterfazCrucigrama();
    }
}