Changing the thumbnail size for products

Hi. I am new to Hikashop, and am having a very difficult time with the installation... I'm trying to make is so that the pages that show all the products display the picture a little bigger (right now it's 100x100). I looked on the web, and found several posts that state that this can be changed by going "in the configuration under the tab Files"
I have no idea how to get there. I'm on the site's admin area, click Components / Hikashop / Configuration, and there's nothing on that page that says "Files."
Can anyone please give the steps to get to that Files tab?

Thanks.