function calltoaction(pre, item, link, post) {
    document.write(pre + '<a href="' + link + '"><img src="' + item + '" border="0"/></a>' + post);
}
//pre-html, image, link, post-html
calltoaction('', '/calltoaction/genf20.gif', '/Link.aspx?linkid=3', '&nbsp;');
calltoaction('', '/calltoaction/sytropin.gif', '/Link.aspx?linkid=1', '&nbsp;');
calltoaction('', '/calltoaction/rejuvenate.gif', '/Link.aspx?linkid=4', '');