[Dan]

There are quite a few ways to do it may want to search in google but this is how i accomplish random banner images on my blog.

PHP Code:

<?php
$data[] = "image1";
$data[] = "image2";
$data[] = "image3";
$data[] = "image4";
$banner = array_rand($data);
// print out whatever with $banner in it
?>

Put that somewhere torwards the top. (With vBulletin you may need to put this in the php files but I am not sure where it would really go.)

PHP Code:

<img href="<?php echo $data["$banner"]; ?>" />

And that would pick the random image!