1, first we open you want to change the background of PPT, if you are ready to change the background of the picture, right click ppt "Background"
2, in the Pop-up Background dialog box select "Background fill" in the Drop-down Select "Fill Effect"
3, in the fill effect select the "Picture" tab, click "Select Pictures"
4, select the location you want to download pictures to open the picture, click "OK"
5, click "OK" back to the Background dialog box, you can choose "Application" (applied to a slide, that is, the current one), click "Apply All" (apply to all slides. )
Now let's look at the effect: