To do Alt + H + P + S on Mac in PowerPoint, download and install Accelerator Keys, then press Option, followed by H, P, then S.
Command: Stock Images
This is how to do Alt + H + P + S on Mac in PowerPoint with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with PowerPoint.
Alt + H + P + S opens the Stock Images gallery, giving you access to Microsoft’s library of professional stock photos, icons, cutout people, stickers, and illustrations for your presentation.