A few words of thanks would be greatly appreciated.

Samsung Galaxy S4: Control your camera with your voice

How to use the S-Voice feature to take pictures with your Samsung Galaxy S4?

The procedure is as follows:

Go to Settings> My Device > Voice Control.

Turn on Voice Control and check the box next to "Camera"
Launch the Camera application and you will see a small microphone icon (indicating that voice command is enabled).
You can take a picture using voice commands like: "Cheese", "Smile" or "Shoot".