will my version of iPhoto (9.4.3) work with Yosemite?
I am planning to buy a new iMac with Yosemite. I am currently using iPhoto (9.4.3) with Mountain Lion. Will I be able to use my iPhoto on the new iMac?
MacBook Pro, Mac OS X (10.7.4)
No. You will be using a newer version of iPhoto. Your images and videos, however, are not stored inside the current iPhoto app. They are stored in a file called iPhoto Library, located in your User folder. The new version of iPhoto will be able to open this library.
What you need to be careful about is making sure you have a backup of your current files, and that you carefully follow instructions for migrating your current files to the new computer.
How to move data to your new Mac using Mountain Lion and earlier - Apple Support