You can use a picture as the background for a slide or slides.

You can adjust the picture's transparency after you add it to the slide.


Insert a background picture on a slide

  1. Right-click the margin of the slide and then select Format Background.

  2. In the Format Background pane, choose Picture or texture fill.

  3. Under Insert picture from, choose where to get the picture from:

    Option

    Use it to

    File

    Insert a picture from your computer or network drive

    Clipboard

    Insert a copied picture

    (This option is unavailable if you haven't Copied a picture.)

    Online

    Search the web for an image

  4. To adjust the picture's relative lightness, slide the Transparency bar to the right.

    Drag the Transparency bar to adjust the image

  5. To apply the background picture to all slides in your presentation, choose Apply to All. Otherwise, simply close the Format Background pane.

Remove a background picture

  1. In Normal view, select a slide that has the background pattern or picture you want to remove.

  2. On the Design tab of the toolbar ribbon, in the Customize group at the far right end, select Format Background.

    The Format Background button is on the Design tab of the Ribbon in PowerPoint

  3. In the Format Background pane, under Fill, select Solid Fill.

    In the Format Background pane, select Solid Fill

  4. Select the down arrow next to the Color button. A gallery of colors appears. Select the white color.

    Your current background is removed, and the background of the slide is now white.

  5. If you want to make the same change to the other slides in the presentation, choose Apply to All at the bottom of the Format Background pane.

Source: Microsoft