Ciao!
Prova con l'operatore di modulo:
Codice PHP:
<?PHP
echo "<Table Border=\"0\" Width=\"100%\" Height=\"160\" Align=\"Center\" Cellpadding=\"0\" Cellspacing=\"0\">";
$db = mysql_connect("$db_server","$db_root","$db_pass");
$res = mysql_db_query("$db_name", "select * from foto");
$num = mysql_num_rows($res);
if ($num ==0)
echo " ";
echo "\n\n\n<Tr>";
for ($i=1; $i<$num; $i++)
{
$id_foto = mysql_result ($res, $i, "id_foto");
$nome_file = mysql_result ($res, $i, "nome_file");
echo "<Td Width=\"25%\" Valign=\"Top\">";
echo "<Img Src=\"$nome_file\">";
if($i%4==0) echo "</Tr>\n\n<Tr>";
else echo "</Td>";
}
echo "</Tr></Table>";
?>