First of all , I have already replied to you on the same theme here:
http://wordpress.org/support/topic/308125?replies=2
second, to do that (if you follow the other post instructions) , if i understand right, you can do in two ways, either edit the SINGLE image
/*** (If you are talking about the menu background) called head-bg.png located here :
http://nwsolarfit.com/wp-content/themes/dfblog/images/styles/Default/head-bg.png to accomodate your images
/*** (If you are talking about body background) called bg-head.png located here :
http://nwsolarfit.com/wp-content/themes/dfblog/images/styles/Default/bg-head.png
to accomodate your images
OR
you will need to add 2 seperate divs at the header section. one floats to left, one to right, both pixel size like image and background attach the images, and one in teh middle.
Third, If you please, next time aggregate all your problems in one single thread.