If you have the original pictures, use that - failing that, there are some
thoughts:
Since it is a PhotoAlbum presentation, those are actually AutoShapes with
picture fills and you cannot right-click the picture and choose Save Picture
As... (this works only with PowerPoint 2002, 2003 and 2004).
You can save to HTML (web page). Look into the folder where you saved the
HTML and you'll probably find the pictures there.
If you don't mind exporting the pictures as slides, save the presentation as
PNG (File | Save As...) - PowerPoint will ask you if you want to export the
active slide or all slides - choose as required.
