It's a problem that has plagued photography for decades; taking pictures without the camera sound disturbing everyone around you. Most digital cameras have the ability to mute the simulated shutter sound but Windows Phone 7 owners aren't so lucky.
Regardless how you have your ringer volume set, that distracting sound is always present once you press the shutter button. For those who have a developer unlocked/jail-broken Windows Phone there's a solution out there.
The solution requires you to modify the system registry (proceed at your own discretion).
- Navigate to HKEY_LOCAL_MACHINE\Audio\StreamClass\Output\10 and set "BypassDeviceGain" to 0.
- Apply the changes, reboot your phone.
Your Windows Phone camera application will now follow the phone's audio settings. Simply mute the ringer and you mute the shutter.