Change Background Format Of Your Slides. Display the slide with the slide background you want to change. With the rectangle tool selected draw the shape over the entire slide to create a background image placeholder.
This opens a new menu on the right side where we can set an image background to the shape. In the Format Background dialog box you can choose a solid or gradient as your background as well as a picture or texture. If you want to change the background fill for all of the slides choose View - Master - Slide Master.
This opens a new menu on the right side where we can set an image background to the shape.
If you want to change the background fill for all of the slides choose View - Master - Slide Master. At the top click Slide Change theme. This opens a new menu on the right side where we can set an image background to the shape. A theme is a preset group of colors fonts backgrounds and layouts.