How to get all custom JComponents from a frame in Java?

Question

Java

I have my JComponent which is a picture:

public class JImage extends JComponent {

    private Image img = null;

    JImage () {
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g;
        g2d.drawImage(this.getImage(), 0, 0, this.getSize().width, this.getSize().height, null);
    }

    void setImage(String filePath) {
        try {
            this.img = ImageIO.read(new File(filePath));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private Image getImage() {
        return this.img;
    }
}

There is a class derived from JFrame with a mainPanel:

class Window extends JFrame {

    int width = 1000;
    int height = 500;
    private JPanel mainPanel;

    Window() {

        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        setLayout(null);
        setSize(width+5,height+28);
        setResizable(false);
        setLocation((screenSize.width-getWidth())/2, (screenSize.height-getHeight())/2);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);

        mainPanel = new JPanel();
        mainPanel.setBackground(Color.GREEN);
        mainPanel.setSize(getContentPane().getWidth(),getContentPane().getHeight());
        mainPanel.setVisible(true);

        add(mainPanel);

        repaint();
    }

    JPanel getMainPanel() {
        return mainPanel;
    }
}

I write main, display a window, add some JImages to mainPanel:

public static void main(String[] args) {
        Window window = new Window();

        JImage ji1 = new JImage();
        JImage ji2 = new JImage();
        JImage ji3 = new JImage();
        ji1.setImage("image1.png");
        ji2.setImage("image2.png");
        ji3.setImage("image3.png");
        window.getMainPanel().add(ji1);
        window.getMainPanel().add(ji2);
        window.getMainPanel().add(ji3);
       
    }

Now, how can I get all the components from mainPanel into an array, but so that they have a type not Component (as in mainPanel.getComponents()), but JImage?
If, for example, I need to change the image using setImage(""), then I can't do it, because the Component does not have this method