iMac Graphics Update
This update fixes an issue that may cause iMac computers to become unresponsive when viewing certain very large JPEG images.
• iMac (Retina 5K, 27-inch, Late 2014)
• iMac (21.5-inch, Late 2013)
• iMac (27-inch, Late 2013)
For more detailed information about this update, please visit: http://support.apple.com/kb/HT204779