Swing/AWT/SWT :: Redrawing Images Causes Flickering On Screen

i'm currently doing my system now and my problem is about inserting an image to my jframe form with thread because if i insert image and when i run it it blinks too slow comparing if i use simple oval it doesnt blink.

why is it that if i wrote the code like this.

public void DrawSnake(Graphics g) throws IOException {
Image image = ImageIO.read(this.getClass().getResource("body1.jpg"));
Image image1 = ImageIO.read(this.getClass().getResource("body.jpg"));
Image headr = ImageIO.read(this.getClass().getResource("headr.jpg"));
Image headl = ImageIO.read(this.getClass().getResource("headl.jpg"));

[Code] .....