Page visuals allows you to choose different background images for certain pages. Just navigate to the Page menu in the top right corner and click "Page visuals".

After clicking "Page visuals," a menu bar appears on the left side of the screen. From this menu bar, you can start editing the page visuals.

Next, click "Customize page visuals"

You can set the background here in a similar way to the workspace visuals. More information can be found here.