Код:

var a:MovieClipLoader = new MovieClipLoader();
var b:Object = new Object();
b.onLoadComplete = function(target_mc:MovieClip)
{
  target_mc.width = 500;
  target_mc.height = 400;
}
a.addListener(b);

_root['workspace_area'].createEmptyMovieClip('bg_image'+0,_root['workspace_area'].getNextHighestDepth());
a.loadClip(this.images_source[0],_root['workspace_area']['bg_image'+0]);