Xml photo gallery transitions

Hi, I have an xml photo gallery which is fully functional but lacking in the bells and whistles department! My actionscript is below - How do I go about creating a resizable border for the large image each time a thumbnail is clicked?

myPhoto = new XML();
myPhoto.ignoreWhite = true;
myPhoto.onLoad = function(success) {
//portfolioTag = this.firstChild;
numimages = this.firstChild.childNodes.length;
spacing = 110;
for (i=0; i<numimages; i++) {
this.picHolder = this.firstChild.childNodes*;
this.thumbHolder = thumbnails.createEmptyMovieClip(“thumbnail”+i, i);
this.thumbHolder._x = i*spacing;
this.thumbLoader = this.thumbHolder.createEmptyMovieClip(“thumbnail_image”, 0);
this.thumbLoader.loadMovie(this.picHolder.attributes.thmb);
this.thumbHolder.title = this.picHolder.attributes.title;
this.thumbHolder.main = this.picHolder.attributes.main;
this.thumbHolder.onRelease = function() {
loader.loadMovie(this.main);
title_txt.text = this.title;
varName.text = this.country;
};
}
};

myPhoto.load(“http://tarantula/gallery/xmlData.aspx?countryName=” + country);

thanks!