I wrote a rather detailed and well-meaning essay in there about resizing photos. It would be good to familiarize yourself with some of the concepts that are involved, particularly the main determinants of file size: image size in pixels, resolution (pixels per inch), and amount of JPEG compression applied. You can get a surprisingly large and detailed photo into 100Kb of space.
When Roger talks about shrinking his photos to postage stamp size to get them under 100Kb, that tells me that he is not going through the normal resizing routine, but rather is simply reducing the image size without changing the other variables.
Read the FAQ and then let's discuss it further. I will attempt to clarify anything in there that is still confusing, and I'm sure some of our gifted photo folks will also weigh in.