Billboard Image Not Staying Fixed One Mobile

When I am viewing the website on a mobile and I click on the menu the billboard image at the top drops down. 
Is there anyway for it to stay fixed? 
https://www.michaelmannphotography.com/portfolio-115/

Sorry, there is not a way for it to stay fixed when the mobile menu is clicked.

Ok, is it possinle with CSS to make the menu open like this then instead.
https://www.gregfinck.com/

Sorry it is not.

ok, thank you. 

Sorry completely different question.
My social link is no longer clickable on Mobile. It works on desktop just not on mobile.

I don't see any social links. Where?

There is my the instagram logo on the home page. www.michaelmannphotography.com

You've added code to the additional CSS that are making those text blocks 400pixels high and covering your instagram button.

Ohh
There is this in the CSS

@media (max-width: 1000px) {
.ssto div, .fixedbg {
height: 400px !important;
}

But if I lower the 400px to 100px the image on mobile gets squished and the text does not show properly.