This method will restrict your folder to come up in Gallery in Android.
1. Create blank text file with name “.nomedia”. Ensure file is without any extension. It can be easily checked in command prompt.
2. Copy this File in folder to which you want to restrict access.
This completes the procedure. Tested on Android Jelly Bean.
Remember this only restricts coming up of contents in Android Gallery and does not password protect as can be done with apps.