y = 0;
ad = new Array(y);
 ad[y++] = "<IMG SRC=\"http://www.oldheritagetaxidermy.com/img/gallery/2.jpg\" border=0\"><br>"
ad[y++] = "<IMG SRC=\"http://www.oldheritagetaxidermy.com/img/gallery/2_1.jpg\" border=0\"><br>"
ad[y++] = "<IMG SRC=\"http://www.oldheritagetaxidermy.com/img/gallery/2_2.jpg\" border=0\"><br>"
ad[y++] = "<IMG SRC=\"http://www.oldheritagetaxidermy.com/img/gallery/2_3.jpg\" border=0\"><br>"
//Continue if more required
x = Math.floor(Math.random()*(y));
document.write(ad[x]);
// -->