Layout of Category Pages

Is there a way to edit the layout of categories?

By default I’m getting a huge image taking up most of the screen. Would like to place the posts within the category into two columns instead of one main column, or get the image shrunk to a not so insanely large size.

I would have thought by default it would have been in the editing of Blog Pages, but I can’t seem to find that option in Customiser.

The page I need help with: [log in to see the link]