WooCommerce - Add Box Frame to Product Image

functions.php

/* Wrap product image with a box container. */
add_action('prima_custom_scripts', 'prima_custom_product_image_box');
function prima_custom_product_image_box() {
	echo 'jQuery(document).ready(function($) {';
	echo '$(".woocommerce ul.products li.product a img, .woocommerce-page ul.products li.product a img").wrap("<div class=\'product-image-box\'></div>");';
	echo '$(".woocommerce ul.products li.product .onsale, .woocommerce-page ul.products li.product .onsale").each(function() { var item = $(this); item.prependTo(item.parent().find(".product-image-box")); });';
	echo '});';
	echo "\n";
}

style.css

/* style product image box */
.woocommerce ul.products li.product a .product-image-box, .woocommerce-page ul.products li.product a .product-image-box {
	border-style: solid;
	border-width: 5px;
	border-color: #DDDDDD;
	padding: 10px;
	background-color: #FFFFFF;
}
/* reset padding and margin and remove shadow effect on product image */
.woocommerce ul.products li.product a .product-image-box img, .woocommerce-page ul.products li.product a .product-image-box img {
	padding: 0;
	margin: 0;
	-webkit-box-shadow: none;
	box-shadow: none;
}
/* remove shadow effect on product image mouseover */
.woocommerce ul.products li.product a:hover .product-image-box img, .woocommerce-page ul.products li.product a:hover .product-image-box img {
	-webkit-box-shadow: none;
	box-shadow: none;
}
/* repositioning sale sticker to product image corner, 5px border + 10px padding = 15px */
.woocommerce ul.products li.product .product-image-box .onsale, .woocommerce-page ul.products li.product .product-image-box .onsale {
	top: 15px; 
	left: 15px; 
}

Tutorial: http://www.primathemes.com/documentation/woocommerce-add-box-frame-product-image/