1)Woocommerce categories thumbnails is a WC plugin default option that’s why it would be better to contact WC plugin support and ask if they have recommended plugins to import/export categories images. Our theme does not have special recommendations for this.
2) a) make a logo category: 8 in a row (small picture) – I have already did this for you
b) Subcategory of the car model: 4 in a row (medium image) – if you are talking about real subcategory page (for example …./kategoria-produktu/mercedes/) – there is no option to do this because subcategory does not have any special classes to change the view type
c) single product (large picture + gallery of other products of this product) – you can choose large layout in Theme Options if you have a large image for the product like we have for the bike version for example http://8theme.com/demo/xstore/bike/product/curae-parturient-aenean/