WooCommerce, Not displaying products images in category

The products have their featured images ok, but they are not shown in the category. It was working fine before, I just added some code to functions.php to separate the products in 3 colums instead of 4, but it dind′t work so I removed that code.

This was the code:

// Change number or products per row to 3
add_filter('loop_shop_columns', 'loop_columns');
if (!function_exists('loop_columns')) {
	function loop_columns() {
		return 3; // 3 products per row
	}
}

Now it just displays the tittles:

Link to one of the categorys