That's the basis you "just" need to a dynamic gallery to the ribbon which can read the images and show and insert then. If you want to tackle this try buying RibbonX Customizing the 2007 Ribbon. It explains how to do this (not simple though) The problem you will hit is that you need jpg images not shapes for the ribbon so you will need to have BOTH in the folder.
It's much easier if you never need to update the shapes easily.
We have a
proof of concept demo you can download.
Close PowerPoint, run the file and then open PowerPoint. Should be obvious how it works.