Emil. Would this work in your excellent Responsive Theme?
Sounds like the steps would be:
1) copy WooCommerce style sheet to child theme (woocommerce.css?)
2) change the image properties that I find there to what you outline:
img {
-ms-interpolation-mode: bicubic;
border: 0;
height: auto;
max-width: 100%;
vertical-align: middle;
}
AM I understanding this correctly?