There are many contributions to manage several images, but all modify many files, as well as the original database.
I thus decided to write this contribution by basing me on "Three images with admin 1.0" of Jason:
http://www.oscommerce.com/community/contributions, the 3432
Principal functionalities are:
- free from 0 to 9 additional images, management in configuration > images > Number of extra images
- creation of an additional table to manage the images (the original database is not modified)
- automatic redimensioning of the images, increased in popup.
Documentation in english, with many screenshot.