Similar to Shape Styles for shapes on your slide, PowerPoint also provides Picture Styles for your inserted pictures. With a single click, Picture Styles can transform a simple looking picture to something more distinct. Note that unlike Shape Styles, Picture Styles are not Theme specific. They just transform your picture to make it look stylish by applying a border, or a 3-D effect, or by changing the frame shape, etc. Follow these steps to apply Picture Style presets to selected pictures in PowerPoint Online.
Learn how to apply preset Picture Styles to your pictures in PowerPoint Online.