Don´t worry it´s not a big problem. Only you need to do is to adjust the settings on your Samsung S4 which will stop auto photo syncing on your android phone.
Follow the instruction below:
1. Go to the Facebook app on your phone
2. Go to your profile
3. From your profile, select photos
4. There should be a synced section on the bottom
5. From synced photos, go to settings in the top right and turn off photo syncing