How to replace an image with a header

Hi everybody, I’d need to make an image be replaced by an header (sticky) with a nav menu in it when scroll. By now the solution I have in place is with the header in white(that’s the BG colour of the page) that changes the colour on scrolling and that works, but leaves too much space on top of the page and in those pages where the BG is an image, the header is visible too early on scroll. Could some one help me please? Thanks

• This topic was modified 2 years, 1 month ago by Jan Dembowski. Reason: Moved to Fixing WordPress, this is not an Developing with WordPress topic

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