Vertical Product Thumbnail Gallery

Add these styles to your Custom CSS

/*
  Placement product thumbs on top of the main image in the product gallery
  Author: Dmitry Kiselyov @_dmitrykiselyov
*/
@media (min-width: 1024px) {
  .ProductItem-gallery {
    position: relative;
  }

  .ProductItem-gallery-thumbnails {
    position: absolute;
    z-index: 900;
    top: 0;
    display: -webkit-box;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
            flex-direction: column;
    margin: 0;
  }

  .ProductItem-gallery-thumbnails-item {
    margin: 0 0 -2px;
    border: 1px solid transparent;
    transition: border 0.4s ease-out;
  }

  .ProductItem-gallery-thumbnails-item.sqs-active-slide {
    z-index: 1;
    border-color: #e4c693;
  }
}