.product .woocommerce-LoopProduct-link .attachment-woocommerce_thumbnail.size-woocommerce_thumbnail.secondary-image {
    position: absolute;
    display: none;
}
.product .woocommerce-LoopProduct-link:hover .attachment-woocommerce_thumbnail.size-woocommerce_thumbnail.secondary-image {
    display: block;
}