Where to remove these gaps?

[fairestcape]

Not sure if this is the cause, but look in:-

includes/templates/template_default/templates/tpl_modules_products_all_listing.php

The first few lines are:-

<?php
/**
 * Module Template
 *
 * Loaded automatically by index.php?main_page=products_all.<br />
 * Displays listing of All Products
 *
 * @package templateSystem
 * @copyright Copyright 2003-2006 Zen Cart Development Team
 * @copyright Portions Copyright 2003 osCommerce
 * @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
 * @version $Id: tpl_modules_products_all_listing.php 4629 2006-09-28 15:29:18Z ajeh $
 */
?>
<table border="0" width="100%" cellspacing="2" cellpadding="2">
          <tr>
            <td colspan="3"><hr /></td>
          </tr>

Try the following:-

<table border="0" width="100%" cellspacing="0" cellpadding="2">

(You may need to increase the cellpadding...)

Remember to save the edited file to:-

includes/templates/classic/templates/tpl_modules_products_all_listing.php