private void saveAsAnimated() {
        String filename = saveAsHelper("gif");
        if (filename != null) {
            try {
                // record that the file should be saved next time
                PrintStream out = new PrintStream(new File(ANIMATION_FILE_NAME));
                out.println(filename);
                out.close();
                
                JOptionPane.showMessageDialog(frame, 
                    "Due to constraints about how DrawingPanel works, you'll need to\n" +
                    "re-run your program.  When you run it the next time, DrawingPanel will \n" +
                    "automatically save your animated image as: " + new File(filename).getName()
                );
            } catch (IOException ex) {
                JOptionPane.showMessageDialog(frame, "Unable to store animation settings:\n" + ex);
            }
        }
    }