You should upload all images to your own website
including backgrounds.
If you worried about space or bandwidth you
can store all images in a photobucket image hosting
account.
that will only work for so long... you can go through those frames with ease....
if you really and I mean really want to stop people from seeing you source one of two options
1. encypt the source code useing jvscript
2. encrypt your source using php
either one of these can also still be by passed however any one who just knwos the basics and possibly know a little bit f andvaced stuff this will intimmidate people from trying to get your stuff