To get started with SyncPhotos, we'll install it on 2 computers named "Stefan's MacBook Pro" and "Elise's iMac".
NOTE: SyncPhotos will not modify your iPhoto Libraries when you install it. It only adds photos and videos to the Library if you manually select some photos and videos, or if you set up automatic sync (explained later).
Both computers need to be on the same "local network" for SyncPhotos to work. This means they should be connected to the same Wifi network (if you're using Wifi) or plugged into the same router (if you're using Ethernet cables).
First, download
SyncPhotos to each computer and double-click on SyncPhotos to launch it. You'll
see a window like this:
Next, wait for SyncPhotos to evaluate all the photos and videos in the iPhoto Library. When it's done, the "cataloging" message at the top of the window will disappear.
Click on the other computer in the source list ("Elise's iMac" in this case) and you'll see all the photos and videos on that computer which aren't already in your iPhoto Library:
To retrieve photos and videos from the other computer, select the ones you want and click "Import Selected"; or click "Import All" to get all of them. SyncPhotos will retrieve them while you wait and import them into your iPhoto Library. When it's done retrieving photos and videos it will prompt you to launch iPhoto. iPhoto will import those photos and videos into its iPhoto Library.
SyncPhotos can also automatically retrieve new photos and videos whenever they're available on the other computer. To learn how to do this, read Automatically Syncing Photos.