Where you don’t have access to use server side processing to place random content into your web page you can use JavaScript to do it for you.
Displaying “Random” Text or Images

About the only effective way of protecting your images on the web is to watermark the images themselves. Any other form of “protection” is useless because the images are downloaded to your visitors’ computers in order for their browser to be able to display the web page and that image file can therefore be easily [...]

Often a web page takes far longer to load than it needs to. Many web beginners forget to properly optimise the parts of their web page. A properly optimised web page might look identical to one that hasn’t been optimised but may be only a small fraction of the total size and therefore will be [...]

With the text and links in your template set up to what you want, the next step in customising your web page template is to change any foreground images. In the fifth NVU tutorial I go step by step through how to do that.
Replacing Foreground Images