Woocommerce category page

Dears,

I am using the Mesocolumn toghether wit Woocommerce and that is working fine.
There is only one thing that I can’t figure out. I want that my subcategories are shown when someone clicks on the headcategory.

They are shown with a picture but the picture automaticly takes the size of the screen. When I add a big picture it is automaticly resized to 150×150 so the resolution is too low…

Does anyone recognize this problem?

See an example here:

https://www.sixpacks.be/product-categorie/keuken-materiaal/