thanks for the effort
this code explains my problem:
when i press the button, i want to copy a panel (living in the
glasspane on the left side) into an image and be able to draw this
image on the right side - completely with alpha values etc.
what it does right now is just removing the alpha values...

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import java.awt.Transparency;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Iterator;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageOutputStream;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;

public class CreateImageTest {
   public static void main(String[] args) {
       JFrame frame = new JFrame();
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

       JPanel panel = new JPanel();
       final JPanel panel1 = new JPanel();
       final JPanel panel2 = new JPanel();

       JButton b = new JButton("copy");
       final JLabel label2 = new JLabel();
       label2.setOpaque(false);
       b.addActionListener(new ActionListener() {
           @Override
           public void actionPerformed(ActionEvent e) {
               Image c = createImage(panel1);
               label2.setIcon(new ImageIcon(c));
               panel2.repaint();
           }
       });
       panel1.add(b);
       panel1.add(new JLabel("haj"));
       panel1.add(new MyAplhaComponent());
       panel1.setOpaque(false);

       Dimension preferedSize = new Dimension(100, 100);
       panel1.setPreferredSize(preferedSize);

       panel2.add(label2);
       panel2.setPreferredSize(preferedSize);
       panel2.setOpaque(false);
       panel2.setBackground(Color.BLUE);

       panel.add(panel1);
       panel.add(panel2);
       panel.setBackground(Color.GREEN);
       panel.setOpaque(false);
       frame.setGlassPane(panel);
       frame.getGlassPane().setVisible(true);
       JPanel backgroundPanel = new JPanel();
       JTextArea textArea = new JTextArea("iufpf w fw ffjoifopfree ef
\n" + ", joiewfeeffjepfie wfeifoewfjepf e\n"
               + " huep heufhfewfeefehufehfueoie\n" + "w
eifehfwefefheo");
       textArea.setPreferredSize(new Dimension(200, 200));
       backgroundPanel.add(textArea);
       frame.getContentPane().add(backgroundPanel,
BorderLayout.CENTER);
       frame.pack();
       frame.setVisible(true);
   }

   public static BufferedImage createImage(JComponent component) {
       Dimension d = component.getSize();
       if (d.width == 0) {
           d = component.getPreferredSize();
           component.setSize(d);
       }

//        GraphicsEnvironment ge =
GraphicsEnvironment.getLocalGraphicsEnvironment();
//        GraphicsDevice gs = ge.getDefaultScreenDevice();
//        GraphicsConfiguration gc = gs.getDefaultConfiguration();
//
//        BufferedImage image = gc.createCompatibleImage(d.width,
d.height, Transparency.TRANSLUCENT);
//        Graphics2D g2d = image.createGraphics();
//        component.paint(g2d);
//        g2d.dispose();

       BufferedImage bi = new BufferedImage(d.width, d.height,
BufferedImage.TYPE_INT_BGR);
       Graphics g = bi.createGraphics();
       component.paint(g);
       return bi;
   }

   public static class MyAplhaComponent extends JComponent {
       {
           setPreferredSize(new Dimension(40, 40));
       }

       @Override
       protected void paintComponent(Graphics g) {
           Graphics2D g2d = (Graphics2D) g;
           g.setColor(new Color(255, 0, 0, 140));
           g2d.setStroke(new BasicStroke(10, BasicStroke.CAP_ROUND,
BasicStroke.JOIN_BEVEL));
           g.drawLine(0, 0, 24, 25);
       }
   }
}

/aksel