imagefield_import.module will allow users with the proper role to be able to import a large number of images into a CCK content type that contains an imagefield.
The migrate module provides a flexible framework for migrating content into Drupal from other sources (e.g., when converting a web site from another CMS to Drupal). Out-of-the-box, support for creating Drupal nodes, users, and comments is included - hooks permit migration of other types of content.