$v = mysql_query("select * from `download` ;");
                    $c = mysql_num_rows($v);
                    $num = rand(0, ($c - 1)); 

$req = mysql_query("SELECT `id`,`name`,`screen`  FROM `download` where `type` = 'file' LIMIT " . $num . ", 1;");
while ($arr = mysql_fetch_array($req)){

echo"<img src='../download/graftemp/".$arr['screen']."' alt='".$arr['screen']."'/>";
echo "<a href='../download/?act=down&amp;id=".$arr['id']."'>$arr[name]</a>";

}