Hi,
Thé size of the category image can be set in the menu options or via css in the front-end css file.
www.hikashop.com/fr/support/153-customize-the-display.html
If the products are not displayed it's probably because you don't have associated a module to the category listing menu.
Go in the edition page of this menu, then click on the link to add an associated module, or edit the associated module, then in the parameters of this module set it to display products.
The export of the orders is in thé Order menu, then on thé toolbar you should find the "export" button.