So the obvious thing to do is re-install. After inserting the DVD and launching Install Bundled Software, I select to do a custom install, but iPhoto is greyed out, and not selectable.
Step forward Pacifist from www.charlessoft.com. After downloading and launching I open the Install Bundled Software package and after a few minutes it shows me the package list. Right click on iPhoto and select Install to Default Location. Every few minutes it would say that something already exists, and I would select 'replace'.
If you have, say, MacBook Air that doesn't have DVD, you can use Remote Disc to copy over the iPhoto package. The packages are in /Volumes/Applications Install Disc/System/Installation/Packages/.packages.
That path is invisible so either use Onyx to show invisibles, or copy from the above path and from the finder do 'apple+shift G' and paste in the path.
Or, after the DVD had mounted, using Remote Disc, you can open the disc from within Pacifist.