Java Swing - 缓冲图像

Question

希望这不是一个重复的帖子，但我真的找不到解决方案。

所以，我想把一张图片放到所有面板上

这是我的代码：

public class MyFrame extends JFrame{

private BufferedImage backgroundImage;

public MyFrame() throws IOException {
    setSize(650, 450);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setTitle("Dragon Game");
    setResizable(false);

    getContentPane().setFocusTraversalPolicyProvider(true);
    getContentPane().setBounds(new Rectangle(0, 0, 650, 450));
    getContentPane().setSize(650,450);
    getContentPane().setLayout(null);


    JPanel gamePanel = new JPanel();
    gamePanel.setBounds(0, 25, 650, 375);
    getContentPane().add(gamePanel);
    gamePanel.setLayout(null);
    try{
        backgroundImage = ImageIO.read( new File("imgs/dragon.png"));       
    } catch (IOException e) {
        e.printStackTrace();
    }
}

protected void paintComponent(Graphics g){
    requestFocus(true);
    setFocusable(true);

    g.drawImage(backgroundImage, 0, 0, this.getWidth(), this.getHeight(), Color.WHITE, null);
}

}

任何想法？