(LibraryHowTo) How to use the camera app when your phone is locked on Windows Phone ?

 To allow the use of the camera app without unlocking the screen of your Windows Phone device, you will need to enable a small option first:

• Open the Pictures app and tap on More (three horizontal dots)
• Tap on Settings (photos+camera).
• Turn on "Press and hold camera button to wake up the phone"

As from now on, your can launch the camera app by simply holding down the camera button for a couple of seconds.