Adding NEW Class to Related Products Images (Woo)

Hey everyone,

I’ve been trying to solve this for the last 3 days, but am lost!

Would like to add a new class to the Related Products imgs.
a. Current classes are: .attachment-shop_catalog and .wp-post-image).

b. I would like to change the classes to: attachment-shop_catalog .wp-post-image and<strong> .MyCustomClass</strong> <– the new class.

I was able to create a wrapper div AROUND the images editing the related.php file, but cannot figure out how to add a class TO the images themselves.

Any help would be GREATLY appreciated! Thank you.