There are many multi image contributions, but I found many have become much too bloated or just didn't fit, so I created this, allowing as many extra product pictures as you want with admin control and fancy lightbox like popups.
1.Its a simple strait forward design, only two files to edit.
2.An un-limited number of additional images can be added to any product without modification.
3.Any product can have as many (or few) images as wanted.
4.Additional images can be deleted if needed.
5.Fancybox is used for the image popups, so all product images can be browsed within a single popup. (Fancybox is like lightbox but better lighter code).
6.Additional image layout can be modified in admin, selecting a horizontal or vertical layout and the number or images to show per row
7.Additional image size is also set in admin.
8.I recommend this is used with OscThumb for auto thumbnailing & faster load times.
9.As a bonus addition, a function is added in the product edit page to give a instant update option.
Fancybox is released under the MIT License, details and examples can be found here .
To work Fancybox is particular about the doc-type used, check at their site & in the installation.
Tested on PHP 4 & 5, SQL 4 & 5, osC 2.2 ms2, rc1 & rc2a and is register_globals off compatible
Support thread will be found here http://forums.oscommerce.com/index.php?showtopic=344580