Two identical while loop functions, the second doesn't work - php

Question

I've got a problem with my php script. The script generates two <ul>'s, one with the images, another with the thumbnails. The php runs through the first while loop perfectly, but my <ul> for thumbnails always comes back empty. I've been working through it to no luck, and I can't seem to get the script to print any errors. Help?
include "../backend/connect.php";
$query = "select image_id from images where thumb != '';";
$result = mysql_query($query);
<div id="main">
<div id="container">
<ul>
<?php
while ($row = mysql_fetch_array($result)) {
$img_id = $row['image_id'];
?>
<li class="hidden" id="<?php print($img_id); ?>" style="background-image:url(/pull.php?id=<?php print($img_id);?>&thumb=false)"></li>
<?php } ?>
<li class="" id="focus"></li>
</ul>
</div>
</div>
<div id="side">
<div id="photos"><ul>
<?php
while ($row = mysql_fetch_array($result)) {
$img_id = $row['image_id'];
?>
<div class="imgDiv" id="<?php print($img_id); ?>" >
<li>
<img src="pull.php?id=<?php print($img_id);?>&thumb=true" class="thumbnail"/>
</li>
</div>
<?php
}
?>
</ul></div>
</div>
</div>

Answer 1

you're using a while loop to loop through the results, you cant do it twice.
Call mysql_data_seek($result, 0); to reset the internal pointer back to the first record after your first time through the results to start over.

Answer 2

It sounds like maybe you read all the rows in the first loop, and there's nothing left to read by the time you get to the second loop :)

Answer 3

Your first while loops until mysql_fetch_array($result) is false/empty. You never assign a new value to $result, so when you get to your second while it skips the loop.
If you want to iterate through the results twice, dump them into an array and use foreach to iterate through it.

Answer 4

The first time you loop through the results, you are actually clearing the $result object. You could possibly loop through once doing something like:
$image_ids = array();
while ($row = mysql_fetch_array($result)) {
array_push($img_ids, $row['image_id']);
}
?>
and then loop through that array while generating your code.