Live Photos, one of the hallmark features of the new iPhone, is prominently featured in Apple's commercials and even jailbreakers can get it on older devices via a recently released jailbreak tweak.
The only problem with Live Photos is that they take up about two times the space of normal images. While iOS's Photos app lets you turn a Live Photo into a still photo with a few taps, the process quickly becomes cumbersome when processing multiple Live Photos.
Besides, the method doesn't really remove anything as you can revert back anytime.
A new iPhone app called Lean from developer Tiny Whale, available for free in the App Store, automates the process of cleaning up one or more unwanted Live Photos, so you end up with their normal representation which helps save storage space on your iPhone.