Phoshare allows you to export and synchronize your iPhoto or Aperture library to a folder tree. It preserves both the original and modified image, your event and album organization, and applies your iPhoto titles, descriptions, keywords, face tags, face rectangles, places, and ratings to the IPTC/EXIF metadata of your images. You can export a full copy of your library, or just build a tree of linked images that require very little additional disk space.