How to add image on top of header logo in child theme?

Question

How do i add an image (icon that will link to photographer's page) on top of my logo
that is already part of my theme, into the child theme functions code, so that it will be saved if i ever upgrade the theme?

I don't know how to use widgets to achieve this nor have I found a suitable plugin.
I currently have it hacked into the parent theme's header file.