applying template to subpages and posts

I have one-page website with 3 posts. As the single page looks great with the theme when I go to gallery or to one of the posts I have a huge problem with the template - specially with the header image.
I would like to use an image as it is in the main page () instead of a static backgroud that in one post is going under the text making it invisible, on some all is ok .
How can I make it to look as on the mian title page?

Hello @marcink,

Please provide live preview of the image malfunction, as well.

I suspect that if you disable the parallax effect from Dashboard > Appearances > Customize, you will get to see the whole image, and not the version that goes for a higher size in height.

Let me know more about it and I’ll see what I can do, but please provide a least a couple of screenshots so I can understand exactly what is going on.