if (document.images) 
{  
img01 = new Image;
img01.src = "../images/but/002o.gif";

img01 = new Image;
img01.src = "../images/but/004o.gif";

img01 = new Image;
img01.src = "../images/but/006o.gif";

img01 = new Image;
img01.src = "../images/but/008o.gif";
}