We generally use cloud storage applications as our primary way to have the back up of our mobile photos. It might not possible all the time to connect your phone with the computer and create the backup of all the images in it, rather it will be good if you can sync those photos with the cloud storage account like DropBox, Google Drive etc. They are preferred because as soon as you get inside the Wifi network you can just launch these applications and they will sync the photos automatically. This way you always have the backup of the photos.
Now this feature has been implemented by Facebook. The biggest advantage of using this feature no Facebook can be the unlimited space offered by Facebook, because all the other cloud storage accounts offer you a limited space. The biggest disadvantage of using this feature can be the threat of getting your account hacked, which might lead to the disclosure of all your private photos on mobile phone. Obviously we do not share everything on our phone with Facebook friends but as Facebook says the synced photos will be stored in a private storage which will only be visible to you and thus if you wish to share any of those photos then just select that photo in the synced section and share it.
For iPhone users, you will have to launch the app then click the photos section as specified in the screenshot below.
Now tap the synced button as highlighted in the screenshot below.
Now you can see all the synced images if you have already started the syncing or you can start this feature from this point.
Please let us know, if you have more queries regarding this feature. For the rest of the information you can refer here.