android hide folder to sd card and share the image inside the hidden folder
If you want to hide folder in Android or any Linux based system just add . as prefix to folder or file name.
However if you mount your SD card on Windows machine then these folders will be visible, with the . in front of the folder name, as a normal folder.
Hide folder with photos on sd card
Include an empty file named .nomedia in your external files directory (note the dot prefix in the filename). This will prevent Android's media scanner from reading your media files and including them in apps like Gallery or Music.