With the pics, you can scan them in at a high
dpi, that way you have a nice detailed image to
manipulate as your starting point, but for fast
downloading, 72 dpi is great.  When you write
the html if you are going it by hand, you don't
even really need to include the image dimensions,
just imgsrc=../images/blarg.jpg or whatever.
If you do define image sizes, make sure you get it
right or things will be distorted. :)  If you
are writing the html by hand and not having a fun
time, you may look into getting a web page 
editor--you can find quite a few to download and
check out at www.download.com for both mac and pc.
I look forward to seeing your gallery once it's
up! :)

Jen