Want to upgrade my IMAC ver OS X Lion 10.7.2

Upgrade them to what? Using Software Update is the best place to start,that will at least get the most current version of Lion. If you want to update to Mavericks first see if your machine meets the minimum system requirements then use the Mac App store to download and install it.

Back up your data, open the Mac App Store, download Mavericks if your system's compatible with it, and then the current version of iPhoto.

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