Is it time to rebuild the thumbnails?

Question

I just noticed two photos are not showing up unless I scroll very fast. Otherwise they are replaced by perforated line frames. This is occuring in library view. In addition fulll screen mode is blank.
I had this when I upgraded from iPhoto 2 to 5 and lost quite a few photos that are dear to me. I am keen to limit the damage this time so any advice on the correct way to proceed is appreciated. BTW I have 2192 items inc 449 short video clips.
mac Mini 1.25ghz/512 ram/combo/mighty mouse/pro keyboard/ LG Flatron 1717s scree   Mac OS X (10.4.7)   Lacie DVD+/- & R/RW writer

Answer 1

Shawdavid:
Are the edit windows dark gray with a dotted square and exclamation point in the middle? If so that's an indication that iPhoto thinks the files are not there when they actually are (unless you've moved, edited or deleted any of them while in the Finder).
You can try a few methods to straighten things out. If the first doesn't help then go to the next. First, however, is to make a backup copy of your iPhoto Library folder.
1 - download and run BatChmod on the iPhoto Library folder with the settings shown here, substituting your account name for mine. You can either type in the path to the folder or just drag the folder into that field.
2 - launch iPhoto with the Command+Option keys depressed and follow the instructions to rebuild the library. Select all options.
3 - if #2 doesn't
Using iPhoto Library Manager to Rebuild Your iPhoto Library
Download iPhoto Library Manager and launch.
Click on the Add Library button, navigate to your User/Pictures folder and select your iPhoto Library folder.
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
In the next window name the new library and select the location you want it to be placed.
Click on the Create button.
Note: It can take some time to create the new library if you have a lot of photos. One user reported that with a library of about 5,000 images it took about 12 hours so plan ahead.
This does not modify the original iPhoto Library folder but just copies the necessary data from the database file and copies the original files.
4 - as a last resort you'll have to start from scratch by creating a new library and importing the Originals folder from your current library. If you have lots of keywords you do not want to lose then follow the instructions in Tutorial #1 first. Then move the current iPhoto Library folder to the desktop and it's Originals file also to the desktop. Launch iPhoto and, when asked, choose to create a new library. Drag the Originals folder from the Desktop into the open iPhoto library folder.
This will give you a new library with your keywords intact and with the same rolls. However there's a good chance that the roll dated will be different but they can be edited back to what they should be.
Give these a try in order and post back with the results.
Do you Twango?