No. Additional images aren't actually attached to products at all. Their are identified when the product_info page is built based on their similarity to the product's main image. So unless you follow the naming convention, they simply won't be recognized.
That said, I once re-wrote the additional images module for a client to display images that he named in a new database table. It wasn't a particularly big change, being very well localized within the Zen Cart code, so you may wish to consider this if you have PHP and basic database skills.



