How do I download or delete my synced photos on Facebook?
Photo syncing was a service that allowed you to back up photos from your phone to a private folder on Facebook. As of July 7, 2016, private photo syncing on Facebook was disabled and we stopped supporting storage for these private backup folders. If you downloaded and logged in to the Moments app, your photos are available to you there.
If you're interested in a tool for organizing and sharing photos, please try the Moments app.