To make an image transparent in PowerPoint, you have to change the opacity of the image - and you can do it for the whole image or a part.

After making the image a bit transparent, you’re ready to add the lines that create the collage effect. How to insert lines to create a collage effect in PowerPoint ...

If you don’t want the same rectangular pictures for your Microsoft PowerPoint slide show, create a custom-shaped picture placeholder and make it available to the presentation via a layout slide.

Learn how to add images to PowerPoint using Microsoft's Copilot and how to generate an image to use for your slides.