What Im looking to get working is to have three thumbnail images and 1 main image already populated, and when you clik the thumb image it takes over the main image, now I know there loads of code on the web to get this working, but unfortunately it isnt as straight forward as a simple click a thumb and change the main.

The problem I have is that the designer wants 4 images, and the way it is at the mo, is that I only have space for 3 thumbs on the right, and the 4th image at the moment is the main large image. So what I would like to happen as I cant accomodate a fouth thumb is that when say the first thumb is clicked it swaps with the main imagem so Ive always got 3 different thumbs on the right and another image as the main, so there 4 images, but only space for 3 thumbs.

Where as what I have seen on the web for this to work, is that I would need to have all 4 thumbs there and on click that thumb populates the large space.

There loads like this one out there which would be easy to replicate for myself.