如何在JFrame上正确显示PNG

我将如何在JFrame上显示具有透明parst的png。
我目前有此代码，一切都很好，但是它显示的透明部分为灰色！

private static void createAndShowSplashScreen() throws Exception {
    Image image = ImageIO.read(TCPServer.class
            .getResource("images/splash.png"));
    BufferedImage img = (BufferedImage) image;

    frame = new JFrame("Splash");
    frame.setUndecorated(true);
    frame.add(new JLabel(new ImageIcon(image)) {
        {
            setOpaque(false);
        }
    });
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setPreferredSize(new Dimension(img.getWidth(), img.getHeight()));
    frame.setBounds((int) (java.awt.Toolkit.getDefaultToolkit()
            .getScreenSize().getWidth() / 2 - img.getWidth() / 2),
            (int) (java.awt.Toolkit.getDefaultToolkit().getScreenSize()
                    .getHeight() / 2 - img.getHeight() / 2),
            img.getWidth(), img.getHeight());
    frame.setOpacity(0f);
    frame.setMinimumSize(frame.getPreferredSize());
    frame.setVisible(true);
}

THX的帮助！真诚的罗伯托！

编辑：IMG

问题解决了：

Image image = ImageIO.read(TCPServer.class
            .getResource("images/splash.png"));
    BufferedImage img = (BufferedImage) image;

    frame = new JFrame("Splash");
    frame.setUndecorated(true);
    frame.add(new JLabel(new ImageIcon(image)) {
        {
            setOpaque(false);
        }
    });
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setPreferredSize(new Dimension(img.getWidth(), img.getHeight()));
    frame.setBounds((int) (java.awt.Toolkit.getDefaultToolkit()
            .getScreenSize().getWidth() / 2 - img.getWidth() / 2),
            (int) (java.awt.Toolkit.getDefaultToolkit().getScreenSize()
                    .getHeight() / 2 - img.getHeight() / 2),
            img.getWidth(), img.getHeight());
    RoundRectangle2D r = new RoundRectangle2D.Double(0, 0, img.getWidth(), img.getHeight(), 25, 25);
    frame.setShape(r);
    frame.setOpacity(0f);
    frame.setMinimumSize(frame.getPreferredSize());
    frame.setVisible(true);