you could even do away with the need for the array if you named your images sequentially. Using alpha_foobar's code to start, let's say you had 4 images. Name them 0.png, 1.png, 2.png and 3.png

change
var index = (new Date().getTime())%images.length;
to
var index = (new Date().getTime())%4;

and change
imageNode.src = images[index];
to
imageNode.src = index + ".png";

Then when you want to add another picture to the list, just name it 4.png and change
var index = (new Date().getTime())%4;
to
var index = (new Date().getTime())%5;