The login page colors, image, copyright and title can be customized by editing the .universal/loginPage.ps1 file.
Customizing the login page
You can host an image by using Published Folders. In this example, we have a dbatools.png file in our local folder.
Next, we can create a loginPage.ps1 file in the repository folder. Add the various colors, text and image URL to customize the login page. As soon as you save this file, you can refresh the login page to see the result.