Random image load new image each time

Hi, first post so hope I have the right section.

Total amateur who has been searching for the answer without much luck.

With help from here (Lurking) I have managed to build a movie that randomly loads three images (probably will end up with more than this).

I would like the movie to load a new image each time the page is reloaded and have ended up with this:

var myImageSequence = 3;
var myRandomNumber = Math.floor(Math.random()myImageSequence)+1;
var myImageName = myRandomNumber + “.jpg”;
loadMovieNum(myImageName, 1);
var a:Array = new Array();
= i;

var stored:Number = Math.ceil(Math.random()*a.length-1);// generate first random number to store in memory
function randomNumber() {
var n:Number = Math.ceil(Math.random()*a.length-1);//generate random number for display
if (n == stored) {
ran();//run function again
} else {
stored = n; //store new random number into memory if not matching
var timer = setInterval(function () {
}, 3);

Obviously not working and would be very grateful if someone could help.