folder access lan and web

for sbs 2003, so far default iis setup, eg, inetpub/wwwroot, default
permissions, security etc
looks like i have to do this differently
have a folder for images, right now directly under wwwroot, using for <img
tags for pics, etc on web pages like ebay, and others, works fine
then i went to share it on the local lan so it will would be easy to copy
/paste files there
after enabling sharing on the network or sharing on the web, and trying to
access files via http, it became pass word protected for http access.
i would like it to be password protected for lan access only, actually so i
can map drive access to it and allow anon access via http
so not sure how to or best way to do it