linked in share button customize image

<li class="ft-slinkedin"><a href="http://www.linkedin.com/shareArticle?mini=true&amp;url=http://html5gap.com/html5-form-input-elements/&amp;title=HTML5 new form input elements&amp;source=HTML5 Gap" onclick="javascript:window.open(this.href,
  '', 'menubar=no,toolbar=no,resizable=yes,scrollbars=yes,height=600,width=600');return false;"><i class="icon-linkedin"></i>Linkedin</a></li>