Hide catagory image on catagory pages?

I made images for each catagory that all say “click here”, so it looks silly when you view it on the catagory page itself. On the catalog page it works fine (as it is).

How can I hide or remove the upload image from the catagory and subcatagory pages or better yet, add a seperate image (one for the catalog page and one for the catagory page(s)).