To make the Photos app background more vivid and unique, you can change it according to the following guidance.
Step 1: Open the Photos app by directly tapping the Photos tile on the Start Menu.
Step 2: Open Pictures library or another program saving photos.
Step 3: Select a picture to have it opened.
Step 4: Right-click any place on the opened picture, and select Set as on the bottom left corner.
Step 5: Choose App background on the pop-up list.
Later, you'll find that the background of the Photos app has been changed to the selected picture.
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