$baglan='<li> <a href="http://www.xxx.com/show_videos/Super/340412/" title="Süper">
<img src="http://www.xxx.com/video/90/12/340412/3.jpg" alt="Süper" />';

preg_match('#<li> <a href="(.*?)" title="(.*?)">\r\n<img src="(.*?)" alt="(.*?)" />#si',$baglan,$videocek);

echo $videocek[1];