Display products by tags

Hi,

I am looking for a way to display my products by tags in a template.
Here is what I have done :

<ul><?php
						query_posts( 'product_tag=-10%' );
						if ( have_posts() ) while ( have_posts() ) : the_post();
							echo '<li>';
								echo '<h3>';
									the_title();
								echo'</h3>';
							echo '</li>';
						endwhile;
						wp_reset_query();
					?></ul>

I am wondering how to retrieve products thumbnails ….
Any help would be much appreciated

http://wordpress.org/extend/plugins/woocommerce/