Help Kriesi ..Creating a Different Header

I took this sample from one of your Enfold examples.. I really like the technique.

I would love to reproduce this technique in my own website with my own image but I can’t get my image to fill the header .. no matter what I do ?

Do I need to make my image large enough to cover the header or is there a way to make a smaller image stretch and fill the header?

Also, how do you get the menu to be inside the image in white font instead of below? I really like the way it looks.

Regards,
Alan
(Just another noob trying to learn!)