I really like your theme. I am using it on WordPress.com.
I note that you (and WordPress) say the theme supports featured images, yet I cannot implement this (I’ve added featured images to each of the pages, but the one image shows up on all pages).
I’ve done a bit of Googling, and can’t find any examples of SemPress sites (either on WordPress.com or self-hosted) that have different header images on different pages.
I also lodged a support request with WordPress.com, and they have concluded that the themes doesn’t support featured images.
Can you shed any light?