php preg_match_all matches pictures in articles

$con = file_get_contents("http://bbs.it-home.org/news/jb-1.html");
$pattern="//";
preg_match_all($pattern,$con,$match);
print_r($match);
?>

输出结果： Array ( [0] => Array ( [0] => [1] => [2] => ) [1] => Array ( [0] => http://bbs.it-home.org/usr/themes/dddefault/images/logo.png [1] => http://bbs.it-home.org/usr/uploads/2012/09/531656480.jpg [2] => http://bbs.it-home.org/usr/uploads/2012/09/2647136297.jpg ) )