The simplest things can be so hard. Drupal core has never had a way to upload an image and then output a thumbnail it. Of course there are dozens of solutions for making thumbnails in the contributed modules repository, but it will be a huge benifit to new users to have this handling out of the box. The time is at hand for making Drupal's core, default installation come with kick-ass image manipulation abilities. Come see what we've got and we're headed in Drupal 7.