We're having a small permissions issue with a WSS site.

We have a WSS site that contains custom, static HTML files and images
that were added in "folders" in WSS via SharePoint. So in FrontPage
you can see a site structure similar to this:

http://server/site
+ _catalogs
+ _private
+ _themes
+ images
+ Lists
+ libraries
+ pages

The "images" and "pages" folders contain straigh HTML files (.htm) and
images (.jpg and .gif).

If the WSS site is set to allow anonymous access, users can see the
HTML and images in the images and pages folders. However, if we turn
off anonymous access, users can see the SharePoint list and form pages
as normal, but they are prompted to login to see the HTML and image
files that are outside of any WSS lists.

I cannot find anywhere to set permissions for WSS users for custom
folders added from FrontPage. Is that possible? How can we allow
read-access to these HTML and image files without having to set
anonymous access to the site?