Hi,
HikaShop uploads your images in the upload folder, so in "images/com_hikashop/upload/". Then, the thumbnails are created in folders:
"images/com_hikashop/upload/thumbnails/XXXxYYYf/" where XXX is the width and YYY is the height you want for the thumbnail.
It's technically not possible to configure HikaShop to generate the ilnk
club2b.pl/images/com_hikashop/upload/med...racja_2054637238.jpg
instead of
club2b.pl/images/com_hikashop/upload/thu...racja_2054637238.jpg
because the "thumbnails" part is coded in hard in the code generating the thumbnails.
So I suppose that on your website, you have a third party extension (probably a system plugin) which replaces the text "thumbnails" to "media-list" on your frontend when it isn't supposed to. That's why the thumbnails do not appear because the URLs are wrong as they are changed by something else.