$i=0;
$say=0;
echo "<table><tr><td width=33% align=left valign=top>"; 
$kayitlar = mysql_query("select resim_url  from resimler"); 
while($kayit = mysql_fetch_array($kayitlar)) {


$i = $i +1;
if($say = 0){
echo"<tr>";
}
echo "<td><img src=".$kayit['resim_url']."></td>";
$say++;
if($i = 3){
echo"</tr>";
$say=0;
$i=0;
}

}
echo "</tr></table>";