I think it's a very important thing. Saving in PDF makes it possible to create a "hard copy" album from a PTE presentation. There are many online album printing services; they usually want you to install some software and to create a sequence of pages that can be used only for one purpose - to print an album - though they might be a basis for an online presentation, too; In PTE we have an opposite problem - we get a perfect online presentation which could make a nice album. A PDF file could be a perfect solution. As to the question which time point of each slide will be taken to form an album page. - First of all you can take the final point ("a fully developed slide") - and that's what is done in PowerPoint when you save your presentation in PDF - Second, you could mark points on the timeline as JudyKay suggested - including even multiple points for different phases of the same slide.