It took some time to write, but it’s not that complicated of a module. The module has some settings for using Imagecache and different types and speeds of transitions.
Currently it only works on Drupal 5 with Imagecache 1.x, but I’ll upgrade it to Drupal 6 using CCK 2 and Imagecache 2.
Did this help you out? It took me a few days to piece together all this information together, I hope this saves you some time (who knows, maybe the future me will be thankful I wrote this down). Let me know your thoughts. email@example.com