This code works for "JPEG" but not "gif" or "GIF".

Why?

// repaint onto a BufferedImage
BufferedImage bufferedImage = new BufferedImage ( width + inset * 2,
                                                height + inset * 2,

BufferedImage.TYPE_INT_RGB);

Graphics2D g2d = (Graphics2D) (bufferedImage.createGraphics());

// redraw using our paintComponent
paintComponent(  g2d );

// write out the BufferedImage as a GIF
ImageIO.write( bufferedImage,
                             "gif" /* format desired */,
                             file );