function ara($bas, $son, $yazi)
{
    @preg_match_all('/' . preg_quote($bas, '/') .
    '(.*?)'. preg_quote($son, '/').'/i', $yazi, $m);
    return @$m[1];
}

$icerik = file_get_contents("adres");
$baslik = ara("alt=\"", "\"", $icerik);
echo $baslik[0];