Loadin Random Pics + Timer

Hi guys

I’ve got this code for random loading images after the main page reload.
I would like to change the image after let say 15sec if the user stay on the one page.
Can you please help?

// Sets the number of images in the random sequence
    // IMPORTANT: Set this number to how many images you have
    var myImageSequence = 11;

    // Creates a random number:
    var myRandomNumber = Math.floor(Math.random()*myImageSequence)+1;

    // Creates the full image name like: 1.jpg
    // IMPORTANT: If you're NOT using Jpegs change jpg to png or gif
    var myImageName = "image" + myRandomNumber + ".jpg";

    // Loads the random image:
    loadMovieNum(myImageName, 1);