images = new Array(5);
images[0] = "<style>#tiercontent_e { background-image: url(template/images/tier_photo_a.jpg)}</style>";
images[1] = "<style>#tiercontent_e { background-image: url(template/images/tier_photo_b.jpg)}</style>";
images[2] = "<style>#tiercontent_e { background-image: url(template/images/tier_photo_c.jpg)}</style>";
images[3] = "<style>#tiercontent_e { background-image: url(template/images/tier_photo_d.jpg)}</style>";
images[4] = "<style>#tiercontent_e { background-image: url(template/images/tier_photo_e.jpg)}</style>";
index = Math.floor(Math.random() * images.length);
document.write(images[index]);