Woocommerce Adding Image CSS to Header

Woocommerce is adding product CSS to the header for the catalog images.

.products li a img {
width: 150px !important;
height: 150px !important;
}

I need it so that I can choose what this says. Simply removing the values in the Woocommerce settings breaks everything.

Ideally, I’d like it to say

max-width: 150px

But it won’t let me do that.

How do I remove this CSS property from the header without removing all of the CSS from Woocommerce?