How to get iPhoto to resume recognizing already imported pictures after Mavericks upgrade
For some reason, the update to Mavericks caused iPhoto to forget the location of my iPhoto library, which was on an external drive.  I held down the option key while loading iPhoto and confirm that the default library was a newly created library on the local drive and that my external drive library was present but not selected it.  When I selected it, I was informed that I had to upgrade it to the most current version.  After this was complete, plugging in my SD card resulting in iPhoto recognizing the existing photos as duplicates.  Unfortunately, unlike the old version it no longer gives any progress as it reads the card and processes it, but at least the issue is resolved.