For a permanent Windows 11 desktop image:
- Open Settings > Personalization > Background.
- In Personalize your background, select Picture.
- Choose the image wanted.
- If the image looks too large, change the fit option and try Fit, Center, or Fill until it displays correctly.
If the background keeps changing every day, check whether Bing Wallpaper is installed:
- Open Settings > Apps > Installed apps.
- Search for Bing Wallpaper.
- If found, remove it, because it can override the selected background.
If the image still does not stay fixed, reset the theme:
- Go to Settings > Personalization > Themes.
- Switch to the default Windows theme.
- Return to Background and set the preferred picture again.