The Mail app in Windows 10 looks pretty good right off the bat, partially thanks to the background image that you see when the window is expanded and then as an overlay to the transparent menu in the left.
If however you don’t like the transparency—or the mage—you can turn off the background picture so it just shows a solid color for the menu bar on the left of the Mail app. What’s more, you won’t see as much of the image when the Mail app is expanded either.
The following tutorial demonstrates how to change the background picture of the Mail application that comes with all versions of the Windows 10 operating system.
An example of the default background picture of the Mail app (Windows 10 version 1809):
How to Change Background Picture of Mail app in Windows 10
Here is how you can change the background picture of the default mail application that you get with all versions of the Windows 10 operating system:
1. Open the Mail application by heading to the Start menu and clicking on the Mail app tile.
2. With the Mail app open, click on Settings and then click on Personalization from the flyout. (click to enlarge screenshot below)
3. Scroll down until you get to the Background section and then toggle on the Fill entire window option if you want it on. (click to enlarge screenshot below)
4. Or toggle off the Fill entire window option if you want to lose the transparency and have the menu a solid color. (click to enlarge screenshot below)
5. Directly beneath the Fill entire window toggle is the pictures that you can click on to select to change the background. (click to enlarge screenshot below)
6. Or you can click on the Browse button and upload your own picture from File Explorer. (click to enlarge screenshot below)
That’s all.