Displaying Image Inside of Original Frame

I have a GUI form called SimpleGUI that is just a single JPanel. My goal is to display my URL image inside of the that JPanel.
When I try to add the image, I don't get an error, but nothing displays. The image DOES display if I create a new JFrame and add my JPanel to that. But then I have two Windows open.

How can I display my image in my original SimpleGUI form? (Code below)

Thank you!

public class SimpleGUI extends JFrame {
    private JPanel imagesPanel;
    private JFrame mainFrame;

    public SimpleGUI() throws IOException {
        super("GUI Page");
        setContentPane(imagesPanel);
        pack();
        setVisible(true);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setSize(new Dimension(500, 500));

        mainFrame = new JFrame();



        imagesPanel.setLayout(new GridLayout());
        imagesPanel.setBounds(0,0,200,200);


        mainFrame.add(imagesPanel);
        mainFrame.setVisible(true);


        BufferedImage img1 = null;

        try
        {
            URL url1 = new URL("http://cosplayidol.otakuhouse.com/wp-content/uploads/2012/06/s-1-1.jpg");

            URLConnection conn1 = url1.openConnection();
            conn1.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");
            InputStream in1 = conn1.getInputStream();

            img1 = ImageIO.read(in1);
        } catch (IOException e)
        {
            e.printStackTrace();
        }


        JLabel wIcon = new JLabel(new ImageIcon(img1));
        imagesPanel.add(wIcon);

    }
}