How to use my own jpg as header in 2.0 Kubrick?

I’m trying to use my own image as the header in 2.0. According to all the documentation I’ve read, I should just be able to upload personalheader.jpg to the \wp-content\themes\default\images directory, and it will work. Unfortunately, that has no effect whatsoever. I’m definitely *not* a PHP guy, but I looked at the code a bit and decided to try to upload my image as kubrickheader.jpg.

This does have an effect. Specifically, my image appears *behind* the default header. You can see the edges poking out from behind it. So, how do I turn the default header off?

You can see the problem I’m having at https://www.bignoisybug.com.

I’d appreciate any help anyone can offer. I like Kubrick because it’s simple, but I can’t stand that big colorful space at the top of the page.

Thanks,
Pete Pollack