I have done something terrible! nopen up, 'event' but if I click on them a triangle with an exclamation point comes up. What have I done, how can I get them back?

Question

I have done something terrible!  now some of my photos will not open up, I can see them in the 'event' but if I click on some of them I get a gray triangle with an exclamation point.  What have I done and how do I rectify it? 

Answer 1

The exclamation shows when the file path/link to the original file has been broken.  Apply the two fixes below in order as needed: 
Fix #1
Launch iPhoto with the Command+Option keys held down and rebuild the library.
Since only one option can be run at a time start with Option #3, followed by #4 and then #1 as needed.
Fix #2
Using iPhoto Library Manager  to Rebuild Your iPhoto Library
1 - download iPhoto Library Manager and launch.
2 - click on the Add Library button, navigate to your Home/Pictures folder and select your iPhoto Library folder.
3 - Now that the library is listed in the left hand pane of iPLM, click on your library and go to the File ➙ Rebuild Library menu option.
4 - In the next  window name the new library and select the location you want it to be placed.
5 - Click on the Create button.
Note: This creates a new library based on the LIbraryData.xml file in the library and will recover Events, Albums, keywords, titles and comments.  However, books, calendars, cards and slideshows will be lost. The original library will be left untouched for further attempts at fixing the problem or in case the rebuilt library is not satisfactory.
OT