Changing the default header image in Home

Hey there,
great theme. I am trying to change the default header under cutomization but there isn’t any option. I can change the headers in pages but since home is not a static page I can’t change the header image under pages. Is there any way to do this? I feel really dumb for asking this but somehow I can’t upload or chose an image in the customazition panel for the headerimage….
apreciate any help,
best linus.