This article explains how to remove the background of a picture in PowerPoint, making that portion transparent. Instructions apply to all versions of PowerPoint for Windows and Mac.
How to Make a Picture Transparent in PowerPoint | Microsoft
If the background in an image is a solid color, it's easy to remove the background so that only the main image is visible. This allows text, another image, or a different color to show through, making it a great way to blend your photos into the slide background.
Open the slide containing the image you want to apply a transparent background to.
Double-click the image. A new tab, Picture Format, appears at the top of PowerPoint.
