How to open iPhoto in Yosemite (10.10.3)
If you had iphoto installed in Yosemite, and you updated to Yosemite to version 10.10.3, you may find iPhoto greyed out with a line though it and unable to open.
To open iPhoto, right click on the iPhoto icon in applications.
Click "show package contents"
Within contents, go to the folder named MacOS and double click on the terminal icon named iPhoto.
A terminal window will open (just minimize it - do nothing else with it) and shortly thereafter iPhoto will open.
**
do not close / exit terminal while running iPhoto - doing so will cause iPhoto to also quit.
Quit iPhoto normally, then quit terminal.