Similar to a feature already available in Google+, on a Help page for the service Facebook says that the feature is currently only a test, and is available for some people who are using the newest Facebook for Android app.
Facebook syncs the pictures you take “as soon as you take them,” however, the app also takes into account the battery level on your phone and your sync settings before it starts uploading.
For instance, you can set the application to only sync photos while you’re connected to Wi-Fi network, rather than potentially running up a huge data bill by synching all your shots over your cellular network. Photos that are synced via cellular network are synced at a smaller size (around 100k), to cut down on the damage it does to your data plan.
Your can check to see if you have the feature available by tapping ‘Photos’ on your Timeline within the Facebook for Android app and seeing if there is a ‘Photo Synching’ option available.
If you don’t want to sync photos when you take them you can also turn the feature off within Facebook for Android.