New update for the folks over at Brattoo Propaganda Software. They have updated their flagship application Duplicate Annihilator
This iPhoto plugin takes on the time consuming task comparing the images in your iPhoto library using effective algorithms to make sure that no duplicates escapes. When found the duplicate will either be marked with a description of your choice to make it searchable or simply moved to iPhoto trash can.
Download a demo version and give it a try.
