I can't find the ICloud icon in System Preferences on my IMac

Ok, IMac running OS X 10.6.8. I am not able to locate the ICloud icon to set ICloud on my IMac to help me share my photos between my iPad and my Android phone. Any Suggestions? Thank you :-)


See this link for the requirements:
My Photo Stream FAQ - Apple Support http://support.apple.com/en-us/HT201317