✔ JFrame und Hintergrundbild?!

import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.Toolkit;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class FrameWithBackGround extends JFrame {

	public FrameWithBackGround() {
		setSize(300, 400);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		setContentPane(new BackGroundPane("b2.jpg"));

		add(new JLabel("Label"));
		add(new JButton("Button"));
		
		setVisible(true);
	}

	public static void main(String[] args) {
		new FrameWithBackGround();
	}

	class BackGroundPane extends JPanel {
		Image img = null;

		BackGroundPane(String imagefile) {
			if (imagefile != null) {
				MediaTracker mt = new MediaTracker(this);
				img = Toolkit.getDefaultToolkit().getImage(imagefile);
				mt.addImage(img, 0);
				try {
					mt.waitForAll();
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}

		protected void paintComponent(Graphics g) {
			super.paintComponent(g);
			g.drawImage(img,0,0,this.getWidth(),this.getHeight(),this);
		}
	}
}