Quick fix to automatically import the photos to iPhoto (any version) until Mark/Space fixes their software:

EDIT: 0. Set MissingSync to download the pictures to a folder
1. Open Automator
2. Add the "Import Photos into iPhoto" action, choose which album it should import to and if it should delete the source files or not.
3. File->Save As Plugin, give it a useful name and choose Plugin For: "Folder Actions", then select the folder MissingSync downloads the photos to.
4. Done! Next time you sync the folder action will be triggered and the photos should be imported to iPhoto.