logo,icon

This code will show the same logo for every product:

<?php
  // code goes in functions.php for your child theme
  add_action('woocommerce_before_subcategory', 'before_item' );
  add_action('woocommerce_before_shop_loop_item', 'before_item');
  add_action('woocommerce_before_single_product', 'before_item');
  function before_item() {
    echo '<img src="http://www.mydomain.com/wp-content/uploads/logo.jpg" alt="Logo">';
  }

If you have different logos for different products, check out this plugin:
https://wordpress.org/plugins/ultimate-woocommerce-brands/
The free version will show brand names as text but you will need the pro version to show brand logos. There seem to be lots of settings so you can customise it.
http://codecanyon.net/item/ultimate-woocommerce-brands-plugin/full_screen_preview/9433984

I have not tried the pro version myself so I cannot guarantee it will be suitable for you.