I did some changes on my site and with a little messing around I figured it out. All you need to do is create a hidden folder in HFS that people cannot see when going to your site. Put all of your image files in that folder and then find out the URL of the image file that you want for your background. The change the body tag to add the background. Here's an example of my code....<body background="http://(yourserver/Images%20for%20Web%20server/background.jpg">
The most important thing to remember is that you should not put protection (ie - passwords) on your hidden folder otherwise you will run into problems with constant prompts to put your user id and password in (that is if you require a password to get into your server). My top most folder is the hidden folder on my server so I leave it open for everyone but it is not visible to the common user. It worked great for me. Here's my site if you want to take a look.
http://www.jdog12345.cjb.net. The images run a little slow because I need more upload bandwidth.
