<?php
	$categ = $_product->get_categories();
	$term = get_term_by ( 'name' , strip_tags($categ), 'product_cat' );
	$category_thumbnail = get_woocommerce_term_meta($term->term_id, 'thumbnail_id', true);
    $image = wp_get_attachment_url($category_thumbnail);
    echo '<img alt="" src="'.$image.'" />';
?>