turkey sandwiches!
Software Update had an iPhoto upgrade for me, so I installed it. After that, the iPhoto icon changed to a generic application icon, and launching iPhoto from the dock gave three bounces and then nothing (don’t you love Mac bug reports?).
Disk Utility’s Repair File Permissions fixed the problem, and now iPhoto is happily “upgrading thumbnails”. Why were my permissions wrong in the first place?
previously: Ow My Brain