Resize image at Flash....(dynamic)

programming flash
1

I have a movieClip (empty) which is used has a placeholder to load external images. I need to fix the max size of that placeHolder to 367367 values, so that if the image has 500400 it will shrink to 367*294 when loaded…And so i used the following code at the placeHolder:

onClipEvent (data) {
        loaded = 1;
        var maxWidth = 367;
        var maxHeight = 367;
        if (this._width > maxWidth || this._height > maxHeight)
        {
                var scaleFactor = this._width > this._height ? maxWidth / this._width : maxHeight / this._height;
                this._width = Math.floor (this._width * scaleFactor);
                this._height = Math.floor (this._height * scaleFactor);
        }
        if (this._height > maxHeight)
        {
                var scaleFactor = maxHeight / this._height;
                this._width = Math.floor (this._width * scaleFactor);
                this._height = Math.floor (this._height * scaleFactor);
        }
}

The problem is that this only works the first time i load an image. After that the images appear much smaller … Can anyone help with the code please?

Thks.