Adjust header image height

I’m trying to figure out how to adjust the header height to fit my image. I have an image that is 262px and there is a gap between the bottom of the image and where the menu bar starts. I am using the Streamline Pro theme. Also, if this is done via css, is there a list of the css tags for gch? I can’t seem to find them.

https://www.ads-software.com/plugins/genesis-custom-headers/