In this tutorial, you will learn how to remove part of an image by applying a very basic ripped paper effect. This is especially useful for cropping screenshots, as shown in the example below.
Here are the exact steps that I went through to achieve this effect in PowerPoint 2013/2016:
Add an image to the slide.
Use the Freeform drawing tool to create a zigzag shape that covers the bottom part of the image.
Select the image first, then select the zigzag shape while holding the Shift key.
Choose DRAWING TOOLS → FORMAT → Merge Shapes → Subtract.
Add a drop-down shadow via FORMAT → Picture Styles → Picture Effects → Shadow.