Change default header image

Hi There

For some reason, when I go to change the default header image with the templates it’s not changing at all. I tried using an existing photo, my photo and even changing themes. I am under customize->Header Image, or I try clicking on the edit photo icon in the top right hand corner.

https://wordpress.com/customize/naturalfitnesslab.wordpress.com

I want to change the default city theme, and i can’t get rid of this darn city high rise theme.

Thoughts?