Tween/AS2 Preloader

Good day

The link below takes you to my favorite preloader tutorial and i have been trying to make it work for me.

http://www.kirupa.com/developer/actionscript/tween_as_preloader.htm

In the tutorial the preloader loads a picture of a flower and this flower picture is in the library of the main movie.

So for example if the flower picture was stored externally how if possible can i make the preloader preload it

THE QUESTION
How can i preload externally stored MC or JPG with this kind of preloader

thank you and have a nice day