I always forget about this little gem that comes with ColdFusion.

Anyway i came across this which is a site wide processing script which encyrpts and also copies all your images to another destination so that you can maintain two working copies of your site.

If you don't want to to cut and paste the code i've put it together in a .rar file here: http://www.andyjarrett.co.uk/downloads/encode.rar