Theme is a combination of background image, window color, and sounds. (The option of Start and taskbar is only available while the color sets to dark.)
You can also turn on or off Transparency effects ④.
In Colors, you can choose your mode as Light, Dark, or Custom ③.If you would like to change the way the picture displays on the background, you can select Fill, Fit, Stretch, Tile, Center, or Span on the Choose a fit for your desktop image field ⑤.You can also select ④ to choose other pictures as the desktop background.
Please go to the corresponding instruction based on the current Windows operating system on your computer: