The first time I reovered orphaned photos I said "NO" to importing orphaned photos. The orphaned photos were saved to a new folder outside of iPhoto Library. I looked at the saved photos. All were small size and many had a filename that included the word "face". I suspect the "orphaned photos" were really just thumbnails. That explains the small size. Note that I didn't say this changed the size of any of my non-orphaned photos. It didn't.
When I said "YES" to importing the salvaged photos, the orphaned photos were saved to an album in iPhoto. They were all small size. My other existing photos did not change size, but many disappeared (i.e., changed to the black exclamation point). This situation persisted even after I completed all the other steps. I'd estimate the most recent 25% of my events had lost their thumbnails and contained very very few, if any, real pictures. Since so many pictures were gone I did not take the Library to my son-in-law. I didn't see the point.
Here's the complete sequence of what I did:
1. start iPhoto while holding down option-command till Rebuild window appears
choose top option, Rebuild photos' small thumbnails; click Rebuild
when this finishes, Quit iPhoto
2. start iPhoto again while holding down option-command till Rebuild window appears
choose third option, Recover orphaned photos; click Rebuild
when this finishes, Quit iPhoto
3. start iPhoto again while holding down option-command till Rebuild window appears
choose fourth option, Examine and repair; click Rebuild
when this finishes, Quit iPhoto
4. start iPhoto again while holding down option-command till Rebuild window appears
choose fifth option, Rebuild from automatic backup; click Rebuild
when this finishes, Quit iPhoto
5. start iPhoto again while holding down option-command till Rebuild window appears
choose sixth option, Reclaim unused disk space; click Rebuild
when this finishes, Quit iPhoto
Tom