How to resize dynamic images

1

i am new in flash and i would like to know how to resize an image if the image width exceed 400px.

here is part of my actionscript

function createContainer() {
_root.createEmptyMovieClip(“myContainer_mc”,_root.getDepth()-1);

//myContainer_mc.lineStyle(5,0x000000,100);
myContainer_mc.lineTo(_root.myWidth,5);
myContainer_mc.lineTo(_root.myWidth,_root.myHeight);
myContainer_mc.lineTo(0,_root.myHeight);
myContainer_mc.lineTo(0,5);

myContainer_mc._x = ((Stage.width-myContainer_mc._width)/2);
myContainer_mc._y = (Stage.height-myContainer_mc._height)/2;

}

function callImages() {

_root.myMCL = new MovieClipLoader();
_root.myPreloader = new Object();
_root.myMCL.addListener(_root.myPreloader);

_root.myClips_array = [];

_root.myPreloader.onLoadStart = function(target) {

    _root.createTextField("filename_txt",_root.getNextHighestDepth(),0,0,100,20);
    _root.filename_txt._x = 70;
    _root.filename_txt._y = 305;
    _root.filename_txt.autoSize = "left";

};

_root.myPreloader.onLoadProgress = function(target) {

    _root.filename_txt.text = "Loading.. "+_root.myClips_array.length+"/"+_root.myImagesNo+" Completed";

};

_root.myPreloader.onLoadComplete = function(target) {

    _root.myClips_array.push(target);
    target._alpha = 0;

    if (_root.myClips_array.length == _root.myImagesNo) {

        moveSlide();
        if (_root.myImagesNo>1) {
            myShowInt = setInterval(moveSlide, (_root.mySpeed*1000)+1000);
        }
    }

};

for (i=0; i<_root.myImagesNo; i++) {
    temp_url = _root.myImages*.attributes.file_preview;
    temp_mc = myContainer_mc.createEmptyMovieClip(i, myContainer_mc.getNextHighestDepth());

}

function moveSlide() {

current_mc = _root.myClips_array[_root.target_mc];
new Tween(current_mc, "_alpha", Strong.easeOut, 300, 0, 1, true);

_root.target_mc++;

if (_root.target_mc>=_root.myImagesNo) {
    _root.target_mc = 0;
}

_root.filename_txt.text = _root.myImages[target_mc].attributes.file_name;
next_mc = _root.myClips_array[_root.target_mc];
new Tween(next_mc, "_alpha", Strong.easeOut, 0, 100, 1, true);

}