Excerpt from functions.php, provides support for WooCommerce archive-product.php. This script detects the orientation of the product thumbnail from the product archive, and wraps the image in a div to allow a CSS style to be applied so as to display the image in uploaded orientation rather then the default square thumbnail.

woocommerce-support.php

<?php
/**
 * This snippet removes the action that inserts thumbnails to products in the loop
 * and re-adds the function customized with our wrapper in it.
 * It applies to all archives with products.
 * Original gist here: https://gist.github.com/krogsgard/3015581
 *
 */

remove_action( 'woocommerce_before_shop_loop_item_title', 'woocommerce_template_loop_product_thumbnail', 10);
add_action( 'woocommerce_before_shop_loop_item_title', 'woocommerce_template_loop_product_thumbnail', 10);

/**
 * WooCommerce Loop Product Thumbs
 **/

if ( ! function_exists( 'woocommerce_template_loop_product_thumbnail' ) ) {

    function woocommerce_template_loop_product_thumbnail() {
        echo woocommerce_get_product_thumbnail();
    }
}


/**
 * WooCommerce Product Thumbnail, show as
 * portrait if original image is portrait,
 * landscape if original image is landscape
 **/
if ( ! function_exists( 'woocommerce_get_product_thumbnail' ) ) {

    /**
     * @param string $size
     * @param int $placeholder_width
     * @param int $placeholder_height
     * @return string
     */
    function woocommerce_get_product_thumbnail( $size = 'shop_catalog', $placeholder_width = 0, $placeholder_height = 0  ) {
        global $post, $woocommerce;

        if ( ! $placeholder_width )
            $placeholder_width = wc_get_image_size( 'shop_catalog_image_width' );
        if ( ! $placeholder_height )
            $placeholder_height = wc_get_image_size( 'shop_catalog_image_height' );
        /**
         * Here is where the magic happens:
         * WP checks the soft-cropped thumbnail dimensions
         * and wraps in a corresponding DIV
         */
        $image_data = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), "thumbnail" );
        $image_width = $image_data[1];
        $image_height = $image_data[2];

        if ( $image_width < $image_height ) {
            $output = '<div class="img-wrap-port">';
            if ( has_post_thumbnail() ) {
                $output .= get_the_post_thumbnail( $post->ID, $size );
            } else {
                $output .= '<img src="'. wc_placeholder_img_src() .'" alt="Placeholder" width="' . $placeholder_width . '" height="' . $placeholder_height . '" />';
            }
            $output .= '</div>';
        } else {
            $output = '<div class="img-wrap-land">';
            if ( has_post_thumbnail() ) {
                $output .= get_the_post_thumbnail( $post->ID, $size );
            } else {
                $output .= '<img src="'. wc_placeholder_img_src() .'" alt="Placeholder" width="' . $placeholder_width . '" height="' . $placeholder_height . '" />';
            }
            $output .= '</div>';
        }

        return $output;
    }
}