Adding Thumbnails - (dynamic xml gallery)

Hi gang…i went over the xml photo Gallery here on Kirupa.
Very nice tutuorial…I also went over the second tutorial - adding thumbnails:

http://www.kirupa.com/developer/mx2004/thumbnails.htm

again - this was a much needed tutorial that i have been looking for - however i really relaly need to know how to create the thumbnails from the large images themselves instead of having to make SEPERATE THUMBNAIL IMAGES for the xml to pull?

Therefore i need to know a code that can resize the original images and load into the thumbnail movieclip.

I tried simply using _width and _height for the thumbnail movieclip - but the spacing between them are far too large - when i isolate the code that contains the data for the thumbnail spacing - no change is made!

HELP PLEASE!?

or even better - does anyone know of a tutorial that clearly outlines what i want to do?