There are a few different ways to get images out of PPT. One is to use File
| Save As and choose Web Page (HTML). You'll get a folder with all the
supporting files -- the images will be in there.
Another is to right-click each image and choose Save As Picture.
Another is to choose File | Save As and choose JPG or PNG from the Save As
Type dropdown list. This saves the entire slide(s) as images, though, not
just the images as images.