Hi,

1.  To Change The Number Of Slide, Please Open File Main.Js And Search For The Following Code And Change The Quantity In SlidesPerView

var sThumb = new Swiper('.product-slider-thumbs', { loop: false, centeredSlides: true, spaceBetween: thumbHorizontal ? 15 : 0, slidesPerView: thumbHorizontal ? 4 : 3, direction: thumbHorizontal ? 'horizontal' : 'vertical', slideToClickedSlide: true });

2. You need to use an image with bigger size for zoom immage. You can check the plugin document here http://i-like-robots.github.io/EasyZoom/