//store the wc thumbs in an array
oil = new Array(4);
oil[0] = "images/big_th/series/oil00.jpg";
oil[1] = "images/big_th/series/oil01.jpg";
oil[2] = "images/big_th/series/oil02.jpg";
oil[3] = "images/big_th/series/oil03.jpg";
oil[4] = "images/big_th/series/oil04.jpg";

//calculate a random index
index = Math.floor(Math.random() * oil.length);

//display the rotating wc thumb
document.write("<img src=" + "\"" + oil[index] + "\"" + "alt='Oil & Acrylic' title='Oil & Acrylic' width=93 height=178 border=0 class=largeThumb>");