Your points are all very true. The method used depends on the reason for resizing. It depends on the resolution you want for the finished product. For printing, I use a high one, but for smaller PowerPoint file sizes, I batch resize a whole album at once. I often make a digital album with PowerPoint to put on a DVD to include with a printed album, and to email. They still look great in PowerPoint presentations and email. Whichever method you choose, don't forget to do your resizing with a COPY of the original!