The iPhoto and OSX version support matrix.

iPhoto version	10.10	10.9	10.8	10.7	10.6
9.6
9.5.1
9.5
9.4.7
9.4.3			10.8.3	10.7.5
9.4			10.8.2	10.7.5
9.3.2				10.7.4
9.3				10.7.4
9.2.3				10.7.3	10.6.8
9.2.1				10.7.2	10.6.8
9.1.5					10.6.7
9.1					10.6.3

Note: I'm basing this matrix off the information I got from Apple. Not every version of iPhoto has been tested on every version of OSX.