So, I decided to try out a banner image this morning, and was extremely disappointed to see the banner is not responsive in design (as the theme is supposed to be responsive).
I used an 800 x 250 image, and expected the image to adjust to size on mobile (hence, responsive). Unfortunately, the image does not resize or adjust its position on either the desktop version or the mobile version of the site.
It would be great if you could issue a fix for this. When I have time, I'll dig in to the CSS as well to see what is broken... however a theme that is sold as responsive, and does not include responsive CSS for the header image is just broken :(