can't select an external editor in photo 11 advanced preferences on a 1mac with OSX 9.3
iPhoto '11: Advanced preferences


  In the Edit Photos pop-up menu (described above), you can make photos
  open in edit view in another application (such as Adobe Photoshop). 
  
  If you choose to edit photos in another application, selecting “Use
  RAW when using external editor” opens the RAW file—not the JPEG or
  TIFF copy iPhoto made when it imported the photo. Important:   If you
  select this option and then edit a RAW photo outside of iPhoto, you’ll
  need to reimport the edited photo into your iPhoto library; with this
  option selected, iPhoto doesn’t automatically save the edited copy in
  your iPhoto library.
  
  Even if you don’t select this option, you can always export the
  original RAW photo from iPhoto and open it using the editing
  application of your choice.




Selecting the IN application (in your case the DSCF0586) will open new window. Select the appropriate application. Your DSCF0586 will be overwritten.