Distributing Movie Clips

This is a very simple problem, but I just can’t seem to be able to solve it. I have images loading into empty movieclips (feeded from xml), inside a container movieclip. The problem I have is that the width of the pictures is not the same and they end up overlaid by each other. How could I evenly distribute the images? Here’s my script:

function contentMain_fn(k) {
tlistener = new Object();
tlistener.onLoadInit = function(target_mc) {
target_mc._x = 20 +(target_mc._width+20)*k;
image_mcl = new MovieClipLoader();

And here’s the website where I arranged the pictures by hand… I’de be grateful even if I got a pointer, where to search with my question.