Need help with changing coordinates of loaded images [renamed]

programming flash
1

Iwonder if anyone can set me straight here:
I’m creating an image gallery that loads different files into a mc using this code, form the tutorial.
it works fine, but in my novice way I cannot figure out how I can change the co-ordinates of the Mc once the image has loaded. I need to do this because the files are different sizes. each image has it’s own button in the menu.
Any light on this would be grateful!

bar._visible = false;
border._visible = false;
this.createEmptyMovieClip("container", "100"); 
my_mc = new MovieClipLoader(); 
preload = new Object(); 
my_mc.addListener(preload); 
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)*100; 
pText.text = "% "+Math.round((lBytes/tBytes)*100);
}; 
preload.onLoadComplete = function(targetMC) { 
container._visible = true; 
border._visible = false; 
bar._visible = false; 
pText._visible = false; 
trace(targetMC+" finished"); 
};