Hi Lindsay
it's done quite easy. The CSS looks like this.
<style>
img.second { display:none; }
a:hover img.first { display: none; }
a:hover img.second { display: block; }
</style>The rendered HTML looks like this
<a href="/collections/...." title="Product Title"><img class="first" src="//cdn.shopify.com/s/files/...." alt="Product Title" /><img class="second" src="//cdn.shopify.com/s/files/...." alt="Product Title" /></a>
