What program and version do you have on your Mac computer - Photoshop Elements and its Elements Organizer or Premiere Elements and its Elements Organizer?
The nature of your question suggests that you may be dealing with Photoshop Elements and its Elements Organizer. If that is the case, please post your question in the Adobe Photoshop Elements Forum.
Your thread has been posted to the Adobe Premiere Elements Forum (video editing)..
Please clarify your program.