This application is considered a legacy. Photos in OS X 10.10 has replaced it.
iPhoto allows you to do more with your photos than you ever imagined. It makes it easy to find, sort, rediscover, and rediscover your favorite photos. You can transform ordinary photos into stunning ones with simple but powerful editing tools. You can also share your photos in many different ways, including slideshows, Facebook and Twitter, as well as professional-quality prints, calendars, cards and photo books. iPhoto is more than just a collection. It's a collection that offers endless possibilities.