On the sample page, the header image is faded into the dark color. Are you using overlays or or did you create an image with that affect. I can seem to duplicate it with the functions in the customizations panel.
I am more specifically talking about the light image coming through the background on the demo page. Did you create that as an image or did you somehow lower the opacity on the color with an image in the background?
We are really sorry but we are little confused, so if you are talking about this background image in demo then it the feature image of page which we have kept in every pages. We hope this will be helpful to you, if not then please let us know.
It seems like there is a bug in the theme that you can’t add/change the “Header Image”. Since I build this website locally I don’t have a URL to send you, but screenshots are attached. Pay please attention to the file 3.jpg there you can see that I removed the black background but still the images doesn’t show.