Theme supports header image. The header image is visible on blog page only (front page with blog posts, or “Posts page” defined under Settings – Reading).
To setup the header image go to Customizer – Header Image
Every post and page has own header image – Featured Image!
Bulk header image
Go to Customizer – Header Image
The posts and pages has own image in the header loaded from “Featured image“. Setup the featured image for each post or page.
Bulk PRO post header image options
Go to Customizer – Posts
To setup header image overlay (color) go to Customizer – Colors and Typography – Content – Featured Image Overlay