This example demonstrates how to create a generated image and save it as a PNG or JPEG file. 
    // Create an image to save
    RenderedImage rendImage = myCreateImage();
    
    // Write generated image to a file
    try {
        // Save as PNG
        File file = new File("newimage.png");
        ImageIO.write(rendImage, "png", file);
    
        // Save as JPEG
        file = new File("newimage.jpg");
        ImageIO.write(rendImage, "jpg", file);
    } catch (IOException e) {
    }
    
    // Returns a generated image.
    public RenderedImage myCreateImage() {
        int width = 100;
        int height = 100;
    
        // Create a buffered image in which to draw
        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    
        // Create a graphics contents on the buffered image
        Graphics2D g2d = bufferedImage.createGraphics();
    
        // Draw graphics
        g2d.setColor(Color.white);
        g2d.fillRect(0, 0, width, height);
        g2d.setColor(Color.black);
        g2d.fillOval(0, 0, width, height);
    
        // Graphics context no longer needed so dispose it
        g2d.dispose();
    
        return bufferedImage;
    }