ช่วยแนะนำ เกี่ยวกับการใช้ session ในการกำจัดสิทธฺ์ค่ะ

 <?php
			if($_SESSION['level_id'] == "1")
				{
					include('left_menu/menu_lev_1.php');
				}
			else if($_SESSION['level_id'] == "2")
				{
					include('left_menu/menu_lev_2.php');
				}
			else if($_SESSION['level_id'] == "3")
				{
					include('left_menu/menu_lev_3.php');
				}
			else if($_SESSION['level_id'] == "4")
				{
					include('left_menu/menu_lev_4.php');
				}
			else if($_SESSION['level_id'] == "5")
				{
					include('left_menu/menu_lev_5.php');
?>

if($_SESSION['level_id'] == "1") {  echo "<a href='xx.php'><img src='aa.png'><a/>" }else{echo "<img src='aa.png'>" }