Custom splash screen

What code can I put in the custom splash screen box on the Company Settings page if I want to set the background photo in the screenshot below? Right now all I have is a white screen.


Right now we don’t support setting up background photo for login page.
You can only set up splash screen for loading page.
You can refer to this doc to set up:

Oh, I see. I thought splash screen meant on the login page. No problem then, thanks.