Change desktop wallpaper to a custom photo in Ubuntu 18.04

Solution 1:

20.04

Settings → Background → click a wallpaper to select it or Add Picture (optional).

18.04

1. Open the Settings application by clicking on its icon that has a gear with a red wrench over it.

2. From Settings select the Background category and click on the Background image.

   

3. Download a new wallpaper .png format image to your Pictures folder or copy an existing .png image that you want to use as a wallpaper to your Pictures folder. In the below screenshot the first three images are wallpaper images that were already downloaded to my Pictures folder. Look for an image that will look sharp and crisp if it is used for a desktop wallpaper.

4. Select the Pictures tab and click on any image to select it as the new wallpaper. The selected image will be surrounded by an orange border when it is clicked.

   

5. Click the green Select button to select the image that is surrounded by an orange border as the new wallpaper.