PHP - Random Numbers Changing

Ello Everyone!

Ok, well I'm making a script with a file uploading thingy, and well, I'm also using a random number to generate a number they must write on a paper and upload it.

Issue: I'm experiencing a slight issue with the random numbers though. Once the user uploads their photo with the numbers, I'll send it to my MySQL database. When it gets to that point the random numbers changes, and the numbers will change. I can not find a way to keep it as is, without it changing until the numbers have been placed into the database.


//Top part

$array = array();
for($i = 0; $i<5; $i++){
$array[$i] = rand(0,20);
}

$randNum = implode($array);


//HTML part
<form method="post" action="" enctype="multipart/form-data">
<table>
<tr>
<td>
Generated Number:
</td>
<td>
<h2>
<?php echo $randNum ?>
</h2>
</td>
</tr>
<tr>
<td>
Group Name:
</td>
<td>
<input type="text" name="group" maxlength="15" />
</td>
</tr>
<tr>
<td>
Photo Taken:
</td>
<td>
<input type="file" name="image"/>
</td>
</tr>
<tr>
<th colspan="2">
<input name="submit" type="submit" value="Register As An Artist"/>
</th>
</tr>
</table>
</form>


//SQL Part
if($copied){
$createArtist = mysql_query("INSERT INTO `artistregister` (user_id, groupname, photo, randomnum) 
VALUES ('".$_SESSION['id']."', '".$groupName."', '".$filePath."', '".$thisRandom."')");
$resetArtist = mysql_query("UPDATE `accounts` SET `isArtist` = '1' WHERE `user_id` = '{$_SESSION['id']}'");
if($createArtist){
if($resetArtist){
echo "Your account is now pending for Artist Access. This could take upto a week.";
$_SESSION['isArtist'] = 1;
}
else{
echo "There was an error, and it had been recorded. Please try again later.";
sendError(mysql_error(), $_SERVER['REQUEST_URI']);
}
}
else{
echo "There was an error, and it had been recorded. Please try again later.";
sendError(mysql_error(), $_SERVER['REQUEST_URI']);
}
}
elseif(!$copied){
echo "There was an error, and it has been recorded. Please try again later.";
sendError("Line 98", $_SERVER['REQUEST_URI']);
}


I've tried looking for different functions, and such, but I'm either not looking in the right place or I'm just making some stupid logical error.

Thank you for looking.