Header Image

Folks: I am using a "Clean Magazine" child theme at http://KillerNoms.com. I was trying something out with my header image, and wound up changing a bunch of things (without keeping track), and when I finally got everything back the way I think it was at the beginning, my header image no longer displays on my static front page if accessing by laptop or tablet. But the cell phone interface does show the image, unless I select "view full site" which reloads the site and makes the header image disappear and be replaced with a pair of three line menu nav images i've never seen on my site before. When customizing the header image, everything looks as if it is set properly. "Enable Featured Header Image on" is set to "Entire Site". "Page/Post Featured Header Image Size" is set to "Full Image". This has to be pure user error, but I've tried everything and am stuck. I'd be very grateful for a nudge in the right direction. Thanks!