Also worth to mention the Node Images module ( http://drupal.org/ project/node_images )

It's dead easy to install (no scary configurations like Imagecache +Imagefield), and it shows an extra tab on the node page that allows users to attach images.

Basically, any node gets it's own gallery, and it shows pictures thumbnails above or below node content out of the box (of course it's themable further on).

Marco