If you have iPhoto 7.0 or later, you can import photos from your iPhoto library to Dropbox using the latest version of the Dropbox desktop application.
Note: This feature is not available if your iPhoto library is already inside your Dropbox folder.
Dropbox for Business users: If you've connected a personal and a work Dropbox, photos will be added to your personal Dropbox.
The application will copy the photos to a top-level folder named Photos from iPhoto in your Dropbox. Within this folder, the photos will be organized into subfolders that correspond to the events from your iPhoto library.