Hi,
1. The page on your link is the details page of the product.
So the image size there is controlled by the setting "Product page image (width x height)" in your HikaShop configuration.
Right now, you must have set 0 and 800 in there.
2. The border effect on the listing is done by the bootstrap library embedded in Joomla because each element has the class "thumbnail'. So if you want the same border effect on the image of the product page, you need to add that thumbnail class to the div where you want the border.
You'll want to edit the file product / show_block_img.php via the menu Display>Views of HikaShop and add that thumbnail class to one of the divs there based on where you want the border to be around the image.