Developer tap tap tap submitted an update for their app Camera+ which included a new feature called VolumeSnap. VolumeSnap allowed users to use the volume controls to take a photo, a feature that many iPhone users have asked for. Apple, however, does not approve of using the iPhone's hardware in this manner. Here's what they had to say to tap tap tap:

Your application cannot be added to the App Store because it uses iPhone volume buttons in a non-standard way, potentially resulting in user confusion. Changing the behavior of iPhone external hardware buttons is a violation of the iPhone Developer Program License Agreement. Applications must adhere to the iPhone Human Interface Guidelines as outlined in the iPhone Developer Program License Agreement section 3.3.7

The iPhone Human Interface Guidelines states:

Users use the device’s volume buttons to adjust the volume of all sounds their devices can play, including songs, application sounds, and device sounds. Users can always use the volume buttons to quiet any sound, regardless of the position of the Ring/Silent switch.
Using the volume buttons to adjust an application’s currently playing audio also adjusts the overall system volume, with the exception of the ringer volume. (Using the volume buttons when no audio is currently playing adjusts the ringer volume.)

Although tap tap tap is disappointed that their app got reject, they are appreciative of the fact that Apple was very informative regarding the reason behind the rejection.

Flashlight apps that use the iPhone 4's LED flash were originally in violation of Apple's policy, but it got changed after a developer encouraged Apple to review it. So tap tap tap is encouraging developers and users alike to submit a feature request to Apple to get this policy changed.

So there you go, if the ability to use the volume buttons to snap a photo is something you desire, make your voice heard!

UPDATE: One of our readers, Flo, let us know that there is way to enable VolumeSnap on the current version of Camera+. Just visit camplus://enablevolumesnap in mobile Safari. Doing so will launch Camera+ and VolumeSnap just works. There is a possibility that doing this will disable the volume control to your iPhone, but closing Camera+ from the multitasking dock quickly fixes it. To disable VolumeSnap, visit camplus://disablevolumesnap in mobile Safari.

I've tried it and it works flawlessly. In fact, I didn't even lose volume control. If you try it out, let us know how it works for you!

[tap tap tap via @justin_horn]