Dashboard background sizing

I did some forum searches but didn't find the answer. It looks like the dashboards are resizing the background image selected to fit the device. I would like the background image to not be scaled. Am I missing someplace to set this behavior or do I need to modify the CSS directly to change this behavior?

Use one of the following

html {
    background-size: auto
}

html {
    background-size: cover
}

html {
    background-size: contain
}

Where do I put this? In the CSS? I tried all 3 options and nothing changed. My background is still too big and doesn't display properly.

That is the right spot to add the css. You could try adding !important; after the setting. E.g.

html {
    background-size: contain  !important;
}