image1 = new Image();
image1.src = "ButtonBivalvesCardiidae.gif";

image2 = new Image();
image2.src = "ButtonBivalvesDonacidae.gif";

image3 = new Image();
image3.src = "ButtonPecten.gif";

image4 = new Image();
image4.src = "ButtonSpondylus.gif";

image5 = new Image();
image5.src = "ButtonBivalvesTellinidae.gif";

image6 = new Image();
image6.src = "ButtonBivalvesVeneridae.gif";