heap memory issue, related with garbage collection

Hi:

My standalone Java program displays a series of PNG files in a JFrame. Those PNG files were screen shots captured earlier with several seconds interval. There are hundreds of those PNG files.

The code is like:

    //the method below is repeated called with some interval: displayPic(++count);
    //so the PNG files are displayed one by one without stop -- like viewing a movie. The only problem is that after displaying about 100 PNG files, out of heap memory error occurs. If I increase heap memory: java -jar -Xmx2024m myJar.jar /pngFolder/
   //I can play more PNG files, but the error still happen eventually. I hope I can do some garbage collection to really solve the problem. Thank you.
    

    private void displayPic(final int picCount)
    {

        String pngFileNameWithPath = xxx; //get PNG file name based on int picCount
 
        final ImageIcon imageIcon = new ImageIcon(pngFileNameWithPath);

        final JLabel picLabel = new JLabel();
        picLabel.setIcon(imageIcon);

        final JPanel picPanel = new JPanel();
        picPanel.add(picLabel);

        _jPanel.add(picPanel, BorderLayout.CENTER);

        _jFrame.getContentPane().add(_jPanel);

        _jFrame.setTitle(pngFileNameWithPath);

        _jFrame.setVisible(true);
    }