Abstract,
Thx - appears similar to the MacOSXHints, I believe.
Your info seems more complete; I might try it, but scratching my head as to why the app requires me to go through gyrations to get back to baseline resolution (and, at some of the smaller picture sizes, 300 DPI won't do it). Also, don't think a simple DPI fix will address saturation issues as noted by original poster.
Question: Using your method, does the resultant book PDF approximate the summation of the individual jpg file sizes (or TIFF files, etc.)?
There's a pretty simple app fix: before sending a book for printing, one could have an option to choose DPI. Or, for simplicity, have 3 resolution options: "original", "medium", or "low". Better yet, let me choose resolution by picture size.
Afterall, people are trying to print books (oftentimes, costly books using photos made with high quality equip) - why would the default be down-res'ed photos?
Thx,
Frank