I worked on & off all day on re-titling photos in one of my Iphoto libraries.
Iphoto hung-up on me and I force quit it.

When I re-started Iphoto all the changes were lost.
I am on an eMac with OS 10.3.9., there is no Save command in Iphoto, and the Help
information says that Iphoto automatically saves all changes so there is no need for a
Save command.

Did I do something wrong, or is it a case of live & learn ?

I checked further and found that all the titles I changed are correctly shown
in the Information Block (lower left corner of window) but the name under the
photo thumbnail is the photo filename (the old title).
If I do a minor change in the title it will appear correctly under the thumbnail.

So my days work is not completely lost, I just have to do a trivial change in
each of several hundred titles.