Picture size in slide show

I was able to complete the tutorial at http://www.kirupa.com/developer/mx2004/xml_flash_photogallery.htm
the tutorial explain how to implement a picture gallery. Picture files in a separe folder are loaded using an xml file.

Problem: now it looks like I can not change the picture size.
I have designed the picture gallery so that pictures 300x200 pixels fit well, but if I have a larger picture it covers part of the page.
Is there a way so that I can load any picture and it will automatically fit in my “frame”.
thanks in advance