Updating An iPod Folder
Once you've created and configured an iPod Folder, to actually copy the specified photos into the folder, simply click the "Update" button in the iPod Folders window. iPhoto Library Manager will proceed to copy your photos into the appropriate folders within your iPod Folder. To avoid unnecessary copying, photos that have not been modified since the last update will not be recopied when updating; only the photos that need to be copied will be. If you want to have your iPod Folder automatically updated whenever you edit one of the iPhoto libraries it draws its photos from, check the "Update Automatically" checkbox in the options sheet, and iPhoto Library Manager will detect when the library has changed and update the iPod Folder as appropriate.
Important: When an iPod Folder is updated, the folder will be cleaned up, and any files not belonging to one of the albums being copied will be removed (with the exception of the "iPod Photo Cache" folder created by iTunes when syncing). Do not use the iPod Folder to store any other files, as they will be removed on the next update