Thanks for this paper. I'm sure it will be very useful for many. I decided to post some comments here, not to your email address, I hope you're reading this forum too.
1) It would be nice to mention, that "Short way" (i.e. save for Web) is preffered for PS CS2 users because:
- it's better to convert image after manipulations and before saving to RGB8, even if it's gray (i.e. black&white photo). "Short way" does it automaticaly for you. It also converts RGB16 or Gray16 (if that was output settings of your scanner) to RGB8. Jpeg compression [still] works better with RGB8 data than Gray8.
- it doesn't put any exif data into image (with "image only" option). Exif has no use for web, though someone can disagree. The more images the more space saved
2) "The long way" - it doesn't affect quality but one can make image smaller playing with image format options: go to Progressive and pick up one of scan numbers 3, 4 or 5 which gives you smaller file size (bottom line in the dialog window)
3) It is always worth to check image size in pixels, not only change resolution to 72dpi... Sometimes after changing dpi you can get something like 782*1420 which is way too big for web (do not assume everyone has huge monitor like you, I'm typing it with my old 15" CRT in 800*600 mode). I usually after changing dpi also correct width or height (i.e. long side - bigger number from two) to 600 pixels. If you planning to embed your pic into forum page don't go more than 720 pixels; as mentioned in some other discussion.