Masthead background image zoomed in

Hi,

First, I’ve been using the Vantage theme for a while and I absolutely love it!

I’m trying to make my background image in the masthead area on my website (www.iammekanik.com) fit the page. As of right now, it just zooms way in and I can only see a small area of the original image. The image dimensions are 9200 x 2342, but no matter how I crop the image in GIMP, it still doesn’t fit correctly. How can I scale the image to fit?

Thanks!
Ty