Inserir imagens em um jFrame usando NetBeans

public class testeForm extends javax.swing.JFrame {
    
    /** Creates new form testeForm */
    public testeForm() {
        initComponents();
    }
    
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    private void initComponents() {
        jLabel1 = new javax.swing.JLabel();

        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
            }
        });

        jLabel1.setIcon(new javax.swing.ImageIcon(getClass().getResource("/teste/burnout.gif")));
        getContentPane().add(jLabel1, java.awt.BorderLayout.CENTER);

        pack();
    }
    
    /** Exit the Application */
    private void exitForm(java.awt.event.WindowEvent evt) {
        System.exit(0);
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        new testeForm().show();
    }
    
    // Variables declaration - do not modify
    private javax.swing.JLabel jLabel1;
    // End of variables declaration
    
}