Photos show up as thumbnail but when I click on them they will not display

Question

Photos show up as thumnails but when I click on them they will not display. I get a exclamation mark in a dotted line box

Answer 1

Hylan:
That occurs when the library has lost the link to the original file. This is a result of a damaged library database file, Library6.iPhoto. You can try rebuilding the library from within iPhoto to see if you can recover the photos by launching iPhoto with the Command+Option keys depressed and follow the instructions to rebuild the library. Select the first three options. However, it's iffy.
You can rebuild the library with iPhoto Library Manager as it create a new library, leaving the original one intact, by reading the AlbumData.xml file and copying what it needs. You will be able to recover the photos, albums, keywords, titles and comments. However, books, slideshows, and calendars will not be recovered. Here's how:
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 User/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: It may take some time to create the new library if you have a lot of photos. Report back on how long it took and how many photos you have in the library so we can give other users an idea of how long it may take.
It that doesn't work you'll have to start over with a new library and import the Originals folder from the old library as follows:
Creating a new library while preserving the Events from the original library.
Move the existing library folder to the desktop.
Open the library package like this.
Launch iPhoto and, when asked, select the option to create a new library.
Drag the Originals folder from the iPhoto Library on the desktop into the open iPhoto window.
This will create a new library with the same Events as the original library if you have the Finder checkbox unchecked in the Events preference pane.
TIP: For insurance against the iPhoto database corruption that many users have experienced I recommend making a backup copy of the Library6.iPhoto database file and keep it current. If problems crop up where iPhoto suddenly can't see any photos or thinks there are no photos in the library, replacing the working Library6.iPhoto file with the backup will often get the library back. By keeping it current I mean backup after each import and/or any serious editing or work on books, slideshows, calendars, cards, etc. That insures that if a problem pops up and you do need to replace the database file, you'll retain all those efforts. It doesn't take long to make the backup and it's good insurance.
I've created an Automator workflow application (requires Tiger), iPhoto dB File Backup, that will copy the selected Library6.iPhoto file from your iPhoto Library folder to the Pictures folder, replacing any previous version of it. It's compatible with iPhoto 08 libraries and Leopard. iPhoto does not have to be closed to run the application, just idle. You can download it at Toad's Cellar. Be sure to read the Read Me pdf file.