I'm completely confused here and would appreciate any help with this code where I'm trying to mask some images loaded into a container clip and distributed horizontally along the gallery but I can't manage to achieve it. I think i have tried almost everything besides looking for similar examples. I know I have the masks there from a trace, but I just can't find the way to mask the loaded images. Thanks for reading...

Code:
myGalleryXML.onLoad = function():Void  {
    images = myGalleryXML.firstChild.childNodes;
    thumbs = images;
    callThumbs();
};

function callThumbs():Void {
_root.createEmptyMovieClip("container_mc", getNextHighestDepth());
container_mc._x = 50;
container_mc._y = 50;
    var clipLoader = new MovieClipLoader();
    var preloader = new Object();
    clipLoader.addListener(preloader);
    for (i=0; i<12; i++) {
        thumbURL = thumbs[i].attributes.thumb_url;
        myThumb_mc = container_mc.createEmptyMovieClip(i, container_mc.getNextHighestDepth());
        myThumb_mc._x = 200*i;
        myThumbMask_mc = container_mc.createEmptyMovieClip("thumbMask_mc"+i, container_mc.getNextHighestDepth());
        myThumb_mc.setMask(myThumbMask_mc);
        clipLoader.loadClip("images/"+thumbURL, myThumb_mc);
    }
}