Header image size

Hi,

I’m trying to use Emphasize theme but I’m having problems with the header image.

On your topic “Customize your header” (http://www.shapedpixels.com/setup-emphasize/customize-your-header) you have an example with a “blue” header image covering the menu bar but I’m not being able to change the size of the image to also cover the menu bar (http://new.mhd.pt/)

Can you please give me a help?

Many thanks and regards.