How to change the page header image (not home page)

@zakra_team – I’m using Zakra with Café content. I have managed to upload images as page headers (not on the homepage, this is fine) but cannot remove the original image from the demo content, see URL above.
If I do so, no image is displayed (see as on a different instance I work with: https://www.italia-amata.de/team/)

The page I need help with: [log in to see the link]