You could probably override this by using custom CSS, but are you sure that’s what you want?
If the image is a photo it will not look right if the aspect ratio is changed.
If the aspect ratio of the header is maintained, it will be very short vertically, on small screens.
Better might be to create a head for each screen width range (phone, tablet, laptop/desktop) and use media queries in custom css to use the appropriate header but that’s a lot of work.