green = new Image();
green.src = "green.gif";

red = new Image();
red.src = "red.gif";

blue = new Image();
blue.src = "blue.gif";

yellow = new Image();
yellow.src = "yellow.gif";

green_d = new Image();
green_d.src = "green_d.gif";

red_d = new Image();
red_d.src = "red_d.gif";

blue_d = new Image();
blue_d.src = "blue_d.gif";

yellow_d = new Image();
yellow_d.src = "yellow_d.gif";