Hi,

Replace the code with this one

.basel-hover-alt.product-type-external .btn-add {
	display:none;
}

.basel-hover-alt.product-type-external:hover .swap-elements {
    transform: translateY(0);
    -webkit-transform: translateY(0);
    -o-transform: translateY(0);
    -moz-transform: translateY(0);
    -ms-transform: translateY(0);
    -sand-transform: translateY(0);
}

As for images, the site you sent has all images with the same size.

Regards