Center an image with createEmptyMovieClip

Hello all,
I am working on an image gallery and I have 2 questions.

Whether I use createMovieClipLoader or just a MovieClipLoader I have been unable to center my images.
I have 12 thumbnails which are loaded dynamically via the loader component. Each of these thumbnail images have an onRelease function which then loads a larger image into a larger movie clip on the same stage to the side. I used to use the loader component for this image as well, but have since added a progress bar and I couldn’t make it work with that. So the problem is that I have not been able to get the larger images to center when I release the thumbnail.
I used the tutorial from Kirupa that shows how to make a progress bar for my needs [COLOR=#cc6600]…ecliploader.htm[/COLOR], but it uses one image size. I am useing both landscape and portrait images for the big movie clip. This tutorial works with *createMovieClipLoader. *This is fine except, if I set the x & y coordinates the image opens from those coordinates and the portrait images are then off center.
I then manipulated the code from the previous tutorial to work with just *MovieClipLoader *which I created on the stage so that I could use the convert to symbol for access to the registration position. Athough I was able to change the registration position, I was still left with the same senario as the images were off center.
Does anyone know how to center landscape and portrait shaped images into a movie clip?

I also would like to kow if anyone knows how to make text a button for previous and next buttons? I just want text and no image or outline, mayb a drop shadow.

Thanks for your time, ~Ernie

///////BigScreen Preloader///////
[COLOR=#000050]bar[/COLOR].[COLOR=#0000d0]_visible[/COLOR] [COLOR=#0000ff]=[/COLOR] [COLOR=#006610]false[/COLOR]; [COLOR=#0000d0]border[/COLOR].[COLOR=#0000d0]_visible[/COLOR] [COLOR=#0000ff]=[/COLOR] [COLOR=#006610]false[/COLOR]; [COLOR=#006610]var[/COLOR] [COLOR=#000050]empty[/COLOR] [COLOR=#0000ff]=[/COLOR] [COLOR=#0000d0]this[/COLOR].[COLOR=#0000d0]createEmptyMovieClip[/COLOR][COLOR=#0000ff]([/COLOR][COLOR=#666666]“container”[/COLOR], [COLOR=#666666]“100”[/COLOR][COLOR=#0000ff])[/COLOR];
[COLOR=#000050]empty[/COLOR].[COLOR=#0000d0]_x[/COLOR] [COLOR=#0000ff]=[/COLOR] [COLOR=#991010]0[/COLOR]; [COLOR=#000050]empty[/COLOR].[COLOR=#0000d0]_y[/COLOR] [COLOR=#0000ff]=[/COLOR] [COLOR=#991010]0[/COLOR];
my_mc = new MovieClipLoader();
preload = new Object();
preload.onLoadStart = function(targetMC) {
trace(“started loading”+targetMC);
container._visible = false;
bar._visible = true;
border._visible = true;
pText._visible = true;
preload.onLoadProgress = function(targetMC, lBytes, tBytes) {
bar._width = (lBytes/tBytes)*415;
pText.text = Math.round((lBytes/tBytes)*100)+"%";
preload.onLoadComplete = function(targetMC) {
container._visible = true;
border._visible = false;
bar._visible = false;
pText._visible = false;

///////Default Loaded Image///////
my_mc.loadClip(“M_0001.JPG”, “container”);

///////Thumbnails to BigScreen///////
img_0001.onRelease = function() {
my_mc.loadClip(“M_0001.JPG”, “container”);