This screencast demonstrates the capabilities of the Image Cropper plugin built exclusively for Movable Type and Melody. It is free and open source.
About Image Cropper:
The Image Cropper Plugin for Movable Type provides a simple user interface for managing and generating custom thumbnails from any image asset managed by Movable Type.
The plugin was specifically designed to addressed the case
where publishers want the ability to produce different thumbnails designed specificaly for certain different locations on a web site.
Furthermore, for each of these locations it is not sufficient
simply to scale the asset in question; rather the publisher
would rather crop the asset in a custom manner for each thumbnail generated.
Finally, in order to properly annotate thumbnails to credit the photographer and preserve any required copyright notices, this plugin allows you place some text on the image accordingly.