How to change presence background from color "when present" to black and white "when not present"

I would like to know how to take my background color pic to switch to black and white when not present so I can see at a glance who's home and who's not

what it looks like now when "Present"

What I would like it to look like when "Not Present"

I saw an old thread about using cobra but the links are broken and I'm also hoping to find an easier way.