woocommerce/templates/content-product_cat.php

<?php
/**
 * The template for displaying product category thumbnails within loops.
 *
 * This template can be overridden by copying it to yourtheme/woocommerce/single-product.php
 *
 * HOWEVER, on occasion WooCommerce will need to update template files and you (the theme developer)
 * will need to copy the new files to your theme to maintain compatibility. We try to do this
 * as little as possible, but it does happen. When this occurs the version of the template file will
 * be bumped and the readme will list any important changes.
 *
 * @see 	    http://docs.woothemes.com/document/template-structure/
 * @author 		WooThemes
 * @package 	WooCommerce/Templates
 * @version     2.5.0
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

global $woocommerce_loop;

// Store loop count we're currently on
if ( empty( $woocommerce_loop['loop'] ) ) {
	$woocommerce_loop['loop'] = 0;
}

// Store column count for displaying the grid
if ( empty( $woocommerce_loop['columns'] ) ) {
	$woocommerce_loop['columns'] = apply_filters( 'loop_shop_columns', 4 );
}

// Increase loop count
$woocommerce_loop['loop'] ++;
?>
<li <?php wc_product_cat_class(); ?>>
	<?php do_action( 'woocommerce_before_subcategory', $category ); ?>

	<a href="<?php echo get_term_link( $category->slug, 'product_cat' ); ?>">

		<?php
			/**
			 * woocommerce_before_subcategory_title hook
			 *
			 * @hooked woocommerce_subcategory_thumbnail - 10
			 */
			do_action( 'woocommerce_before_subcategory_title', $category );

			/**
			 * woocommerce_shop_loop_subcategory_title hook
			 *
			 * @hooked woocommerce_template_loop_subcategory_title - 10
			 */
			do_action( 'woocommerce_shop_loop_subcategory_title', $category );

			/**
			 * woocommerce_after_subcategory_title hook
			 */
			do_action( 'woocommerce_after_subcategory_title', $category );
		?>

	</a>

	<?php do_action( 'woocommerce_after_subcategory', $category ); ?>
</li>