Alison:
To make the gallery narrower, you can set the table width in real.htm - the
default appears to have no width specified.
Using the layout tab, you can specify how many pictures per row you want.
There is no option for the "slide show" to set the number of pictures that I can see
I edited the table width here in the real.htm file
<table border="0" cellspacing="0" cellpadding="1" width="500" dir="ltr"
It was 700, but I changed it to 500
slide show is a different animal. I'm not sure you can change the layout
without "heroic" measures.
If it can be done it'll be in the photogallery pages (not the ones you made
but the ones FrontPage generated) and the JavaScript file that goes with it.