How do I insert an image in the center of my JFrame?

Hello guys,

I am trying to create a game launcher (as I have to do that for homework) and I am trying to insert an image. However, I am not able to do it!

If someone could help me, I would appreciate it a lot.

Here is the code:

package javatutorial.net;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import javax.swing.*;


public class SimpleJButton {


    SimpleJButton() {

        //WINDOW
        JFrame f = new JFrame("Launcher");
        f.setBounds(650, 300, 720, 480);
        f.getContentPane().setBackground(Color.black);

        //PLAY BUTTON
        JButton b = new JButton("Jugar");
        b.setBounds(215, 450, 150, 50);
        b.setFont(new Font("Courier New", 15, 30));
        b.setForeground(Color.YELLOW);
        b.setBackground(Color.BLACK);


        //SELECT GAME
        JLabel label = new JLabel();
        label.setText("Seleccionar joc:");
        label.setFont(new Font("Arial Black", 15, 30));
        label.setForeground(Color.RED);
        label.setBounds(150, 5, 1000, 100);


        //empty label which will show event after button clicked
        JLabel label1 = new JLabel();
        label1.setBounds(10, 110, 200, 100);


        //OPTIONS
        JComboBox game = new JComboBox();
        game.setBounds(160, 100, 250, 50);
        game.setForeground(Color.white);
        game.setBackground(Color.darkGray);


        //comboboxmodel
        DefaultComboBoxModel gamemodel = new DefaultComboBoxModel();

        //IMAGE
        JLabel jl = new JLabel();
        jl.setIcon(new ImageIcon("games.jpg"));
        jl.validate();


        //FINESTRETA
        f.add(label1);
        f.add(label);
        f.add(b);
        f.add(game);
        f.setSize(600, 600);
        f.add(jl);
        f.setLayout(null);
        f.setVisible(true);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        game.setModel(gamemodel);
        gamemodel.addElement("Ping Pong");
        gamemodel.addElement("Snake");
        gamemodel.addElement("Brick Breaker");

//action listener
        b.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                String selected = (String) game.getSelectedItem();
                try {
                    ProcessBuilder pb = new ProcessBuilder("java", "-jar", "C:\\Users\\Jose\\IdeaProjects\\PingPong\\out\\artifacts\\PingPong_jar\\PingPong.jar");
                    ProcessBuilder sb = new ProcessBuilder("java", "-jar", "C:\\Users\\Jose\\IdeaProjects\\Snake\\out\\artifacts\\Snake_jar\\Snake.jar");
                    ProcessBuilder bb = new ProcessBuilder("java", "-jar", "C:\\Users\\Jose\\IdeaProjects\\Brick Breaker\\out\\artifacts\\Brick_Breaker_jar\\Brick Breaker.jar");

                    ProcessBuilder selectedGame = null;

                    if(selected.equals("Ping Pong")){
                        selectedGame = pb;
                    }
                    else if(selected.equals("Snake")){
                        selectedGame = sb;
                    }
                    else if(selected.equals("Brick Breaker")){
                        selectedGame = bb;
                    }
                    else{
                        System.out.println("Joc desconegut...");
                    }

                    selectedGame.start();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            private void gamemodel(String selectedItem) {
            }
        });
    }
    public static void main(String[] args) {
        new SimpleJButton();
    }
}