I have found a better way. One that doesn't involve resync'ing the entire stream.
- Quit iPhoto
- Open up Activity Monitor
- In the search field enter:
- Select all the
PhotoStreamAgent processes listed
- Click the
Quit Process button
- In the confirmation dialog that pops up click the
- Confirm that all the
PhotoStreamAgent processes are no longer alive by waiting for the Activity Monitor window to show no processes with that name
- Re-start iPhoto
When you restart iPhoto it will re-start the
PhotoStreamAgent process for your iPhoto session and kick off a new Photo Stream sync. You'll get your lastest pictures updated and you won't have to sit through a full re-sync of all your Photo Stream.
Update for Yosemite where the process name has changed to
iCloud Photos. This is the what you want to kill:
Update for Yosemite 10.10.4 where the process name has changed to
Photos Agent. This what you want to kill:
You can also do this, quickly, from the command line like so:
sudo pkill cloudphotosd
sudo killall cloudphotosd
Photos.appwhich has (pointlessly) replaced an excellent iPhoto app.