I don't know how to install a custom icon to identify a program for the empty desktop, but I was able to use ArtRage to create an icon for me as a user on my Microsoft 10 Accounts. I used a 1-inch square canvas, set at 150 pixels. There is some "fade" at the corners, so I needed to allow for that. I saved it as a png then went to "Settings" "Accounts" "Your Info" "Create your Picture" "Browse", then opened my tiny 1-inch image. I will watch this thread to see if someone knows how to make a custom icon to open ArtRage from the desktop. (Years ago my daughter made one called "Internet Exploder" to open her browser from her desktop, but I have no idea how she did it.)