Why does photo stream on my i phone have more of my pictures than photo stream on my mac?
See http://www.apple.com/support/icloud/photo-stream/ for set up information, FAQ and troubleshooting help
Log out of iCloud in the System/iCloud preference pane and disable Photo Stream in iPhoto's Photo Share preference pane. Then log back in and re-enable, respectively. That should jump start Photo Stream on your Mac.
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