Automatic resize of dynamic images?

Hello once again.

Im looking to get a dynamically loaded image to automatically rescale into a certain area. The code that I have once a sub section on my combobox has been clicked is as follows.

 
function setSubComboArray() {
 mySelectedItem = main_cb.getSelectedItem().data;
 title.text = main_cb.getSelectedItem().label;
 // trace(mySelectedItem+"/"+mySelectedItem+".jpg");
 loadMovie(mySelectedItem+"/"+mySelectedItem+".jpg", "_picWin");
 loadVariablesNum(mySelectedItem+"/"+mySelectedItem+".txt", 0);
}

I am trying to get all images that i have within the selected folder to automatically resize. I dont really want to do this in a photoediting programme, but at the moment i can see no other option. Can anyone help me out on this.