Привет!
<ul>
<?php foreach (get_terms('product_taxomy') as $cat) : ?>
<li>
<img src="<?php echo z_taxonomy_image_url($cat->term_id); ?>" />
<a href="<?php echo get_term_link($cat->slug, 'product_taxomy'); ?>"><?php echo $cat->name; ?></a>
</li>
<?php endforeach; ?>
</ul>