Make sure that all the pictures you want to add are located in the same folder as the current slide show pictures.
- Open Desktop Background by clicking the Start button
- In the search box, type desktop background, and then click Change desktop background.
- If you don’t see your slide show pictures, click the Picture location list to view other categories, or click Browse to search your computer for the folder where the slide show pictures are located
- Point to each picture that you want to add to the slide show, select its check box, and then click Save changes.