New image format from Apple, HEIC stands for High Efficiency Image File Format.
HEIC will be used by default on new photos on iOS 11, and it’s designed to save you storage space. High Efficiency Image File Format (HEIC) is a new image container format from the developers of MPEG, a popular audio and video compression standard.
Apple’s new image format is awesome: same quality, less space hungry. But what about compatibility with older macOS versions or Windows? You will need to use a convertor to convert .heic to .jpg
The free tool to convert HEIC to JPG : Download for Mac or PC