Change thumbnail preview

I'm trying to figure out how Illustrator CC (Version 21.1.1 (64 bit) on Windows 10) determines which artboard it uses to generate the files thumbnail. I thought it chose the original artboard, but mine is using the most recently created artboard. I don't want the icon to be a section of my file notes. I would rather it show some of the artwork so I can quickly identify if its the file I want.

I know naming the files properly helps but with so many files its nice to have a proper preview.