images = new Array(1);// The number in brackets above says how many images there are to be picked from, so add +1 as you add more. Likewise, when you take one away, change it.
images[0] = '<img src="random_images/header1.jpg" alt="Dorothy Stringer">';
images[1] = "<img src='random_images/header2.jpg' alt='Dorothy Stringer'>";
images[2] = "<img src='random_images/header3.jpg' alt='Dorothy Stringer'>";
images[3] = "<img src='random_images/header4.jpg' alt='Dorothy Stringer'>";
images[4] = "<img src='random_images/header5.jpg' alt='Dorothy Stringer'>";
images[5] = "<img src='random_images/header6.jpg' alt='Dorothy Stringer'>";
images[6] = "<img src='random_images/header7.jpg' alt='Dorothy Stringer'>";
images[7] = "<img src='random_images/header8.jpg' alt='Dorothy Stringer'>";
images[8] = "<img src='random_images/header9.jpg' alt='Dorothy Stringer'>";
// The next image in the sequence begins with images[2] and so on. If you remove one, amend the numbers.
index = Math.floor(Math.random() * images.length); // This picks the random image from above
document.write(images[index]); // This is the snippet that picks and puts the random image in