The iPhone 6S' new Live Photos feature, which produces short "moving images" when a photo is taken, is sure to wow consumers when the gadget ships later this month. But unsuspecting photographers may not realize that the images produced are substantially larger than normal photos and can max out storage capacity in a hurry, especially on the 16GB version of Apple's new smartphone.

Techcrunch Editor-in-Chief Matthew Panzarino explained in a video that the new feature takes one 12 megapixel photo, then uses related data from several images capture moments before and after to create a moving picture. That effectively doubles the size of the image. Panzarino explains that the camera works by constantly taking photos and only storing a photo when the shutter is pressed: Live Photos simply keeps the surrounding data before and after the shutter press.

The news has the potential to catch users off-guard. The feature can be switched off, but it is a key selling point of the device as it takes advantage of the pressure-sensitive "3D Touch" screen to activate the moving photos when the screen is pressed hard. Users of devices with low storage will have to decide whether to switch on the feature and experience the latest and greatest, or shut it off and miss out on one of the phone's most interesting additions.

Apple has also put the strain on video shooters by upgrading the resolution to 4K, up from 1080p on the iPhone 6. A single minute of 4K footage takes up over 300MB of space, meaning a 16GB iPhone with absolutely nothing else on it can store around 30 minutes. Like Live Photos, 4K is optional.

The added strain of these new features will be felt most by 16GB phone owners and may leave them having to miss out on new features. In a previous interview, Apple SVP Phil Schiller explained that the 16GB device is still sold as some are less interested in storing all their data on their phone, opting instead for an iCloud subscription.