Add an image as a button to mainHeader

Hello to all. First time here, looking to solve a problem with mainHeader, in Freddo free theme.

Let me explain the situation. I need to add an image acting as a button in between “freddoSubHeader title” and “freddoSubHeader”, in div.mainHeader.

The purpose of this image as a button is to always stay visible, when the sticky menu is scrolled down, and also in the mobile view.

Can anyone direct me, with a code snippet, how to achieve this, in Freddo free theme?

Thank you all for your time reading this post.