fixed image below header

andreasconow

Hi,

I want to have a fixed background image for my entire website, the image shall cover the whole screen, but it must begin only under the header (not stretch behind the header) since the upper top of the image has a color gradient so it will gradually blend into the header color (in case the image stretches behind the header this gradient will not be visible).

The header is manually created using the Header Builder.

I uploaded the desired image under

"theme options - global - general - background"

First question: Which settings do I have to use so that the picture will cover the whole screen on any device?

Second question: With any setting I try, the image seems to be stretching in the background behind the header, so the visual gradient is not visible. What do I need to do to let the upper top of the image start exactly under the header?

Thanks!