Shell Programming and Scripting

So right now I am trying to sync an iPhoto Library file from multiple computers.

The goal being that it takes the most recently updated file (depending on which computer it was). Currently I am using Google Drive to essentially sync the newest library, however, I was curious to see if this was possible using my own server. I believe RSYNC won't work the way I had originally intended

Code:

rsync -avz --delete --exclude '.DS_Store' xxxxxx@xxxxxx.com:/Users/xxxxxx/Pictures/ /Users/xxxxxx/Pictures

This sometimes deletes the newer file and updates with older file. Keep in mind these pictures are not stored in a normal directory but a file thats 'iPhotoLibrary.photolibrary'

Any suggestions would be greatly appreciated. I am running out of ideas on how to streamline this

Thanks
Andrew =)

Code:

man rsync

tells about -u option.