The css was edited as follows:
and the layout as follows:
The key in this screenshot is: "customIcon": "he-blank"
This made the writing that usually shows up on the button hidden. Then the image was added like this:
Note the image file is a reference to an image that is saved on my Hubitat. HE allows for files to be stored on it. This means this dashboard images will only show up on a local dashboard. That is fine by me, but if you want both local and cloud you would need to host these files elsewhere.
I basically figured out how to do all this by reading this post:
