Thanks for the answer Ray.
I have used a number of carts and the method I found best was to include a number of fields for image paths in the products table.
This keeps the table structure very simple. It does not allow for an unlimited number of images but the inclusion of say 10 fields for image paths should satisfy most situations.
I have used carts where an unlimited number of images can be accomodated but this needs two tables and causes image additions to be much more complicated.
There are some excellent website product image displays and my favourite is a fashion site is
If you have a look at a typical display page eg
I think you will agree the display is quick and elegant.
I believe the best image display possible is essential for product sites, after what else is the to show a customer.