DIV element not being pushed down by content inside it

I have a div which is not being pushed down by the content inside it. Instead the content just overlaps the div. I assume this is because there's a PHP while loop between the div tags? How do I fix this?

<?php 
 session_start();
 if (!$_SESSION["user_name"])
 {
 header("Location: index.php");
 }
 include('header.php');
 $id = $_GET['id'];
 if(isset($id)) {
 connect_to_db();
 mysql_query("DELETE FROM content WHERE id='$id'");
 $deleted = 'Content Successfully Deleted.<br>';
 }
 echo '<div id="content">';
 echo '<h2>Delete Content</h2>';
 if(isset($deleted)){
 echo $deleted;
 }
 connect_to_db();
 $query="SELECT id, date, title, image FROM content ORDER BY date DESC";
 $result=mysql_query($query);
 while($row = mysql_fetch_array($result)){
 echo '<div id="delete" align="center">';
 echo '<a href="delete.php?id='.$row['id'].'"><img src="'.$row['image'].'" style="border:1px solid black; width:100px;"><br>Delete</a>';
 echo '</div>';
 }
 echo '</div>';
 ?>
 

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