There’s a few ways of adding images there…first is the custom header found under Appearance >> Header.
The other is using the Showcase widget position which usually means adding a photo to a text widget.
The banner widget position is styled differently and this one will show up on other pages, but it won’t show until a photo is added via a widget.
With either the first or second one, you will get those outer boxes showing again which only show when something is there. The WP header one has a button on the page to restore the default image labeled as “Restore Original Header Image”.
