fails to set the size of a frame

[nidheeshkumar.r]

hey,

i cant set the size of a frame to a particular dimension.My code is :-

public class ImageShow extends JFrame{
    
    ResultSet r;
    Image img;
    public ImageShow() throws SQLException
    {
        setTitle("Image retrieved");
        JPanel panel = new JPanel();
        //setSize(500, 500);
        setDefaultCloseOperation(HIDE_ON_CLOSE);
        Container pane = getContentPane();
        panel.setLayout(new GridLayout(3,3));
        r=ImageRetrieve.rs;
        while (r.next())
            {
                byte[] imagedata = r.getBytes("image_path") ;
                img = Toolkit.getDefaultToolkit().createImage(imagedata);
                img = img.getScaledInstance(200,200,Image.SCALE_SMOOTH);
                ImageIcon icon =new ImageIcon(img);
                JLabel Photo = new JLabel(icon) ;              
                panel.add(Photo) ;                
                this.pack();                         
            } 
        
        JScrollPane scrollpane = new JScrollPane(panel,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
        pane.add(scrollpane);
        this.setPreferredSize(new Dimension(500,500));
        this.setVisible(true);   
    }
    }

here i've retrieved the images stored in a database and tried to display it in a gridLayout.But after adding the scrollbar,when i run the above code the new frame appers as very small,and i have to manually stretch it to a convenient size...but all other things are working well...now i just want to display the frame with specified size...is there any problem with the code??
thanks in advance :)