One of the new features of the iPhone 6s is Live Photos. Turned on by default, this feature captures images for 1.5 seconds before and after the actual still photo that you take. When you tap on your still photo, you see what appears to be a three-second video of that moment. As you can see in the embedded video below, a still photo of rippling waves can show the actual rippling when you touch the display. Apple emphasized, however, that this is not a video, and that it doesn't greatly increase the file size. Any Live Photos you take can be viewed across iOS devices. And they appear as simple jpeg images when viewed on other devices.
According to a post on 9To5Mac, the images created by the Live Photos feature are, instead of being video, similar to animated gifs, but in a jpeg format. Apparently they take about about twice the space of a regular photo.
So how does it work? How does the camera know when you're going to take a photo so that it can begin capturing images 1.5 seconds before you tap the button? The post points out that the camera on iOS devices actually begins recording images as soon as you open the app. That's how your camera is able to take photos instantly without any lag. It's constantly storing images and just keeps the one that's recorded the moment you tap the button. Live Photos simply keeps additional images from slightly before and after you take the photo and then puts them together in an animated jpeg.
When Apple introduced this feature, there was some concern about the fact that the camera is constantly capturing images whether you're taking a photo or not. But Apple allayed those concerns when raised by TechCrunch, saying that any images that are recorded are quickly overwritten by other images, until such time as you decide to take a photo. According to Apple's statement, “Although the camera is 'recording' while you’re in Live Photo mode, the device will not save the 1.5 seconds before until you press the camera button. The pre-captured images are not saved to the user’s device nor are they sent off the device.”
I like this feature, and I think it will be popular. Here's the segment from the September 9 event in which Apple introduces and demos the Live Photos feature:
