HEIC, High Efficiency Image Format (.heic)
The HEIC Raster image file format
HEIC is the new standard image format introduced by Apple with its 2017 update from iOS 10 to iOS 11. It is also known under the acronym of HEIF which stands for High Efficiency Image Format. The HEIC format was developed by MPEG (Moving Picture Experts Group) which are otherwise known for video and audio formats such as MP3 or MP4. Being the new default or standard image format for iOS 11 devices, HEIC was designed to replace the JPG format. It's smaller in size with comparable quality while also supporting transparency. Furthermore, HEIC files can contain several images which fits Apple's "Live Photo" functionality. Furthermore, it stores information about image editing like rotation and cropping which enables the user to revert the changes later on.
Technical details of HEIC files
The lossy compressed HEIC format is based on HEVC (High Efficiency Video Compression), which was also developed by MPEG. Together with transparency and the ability to store more than one image, HEIC files can also contain 16-bit colors, whereas JPG files can only support 8-bit. HEIC files still have some compatibility issues, even though they are already posted and saved to social media or cloud storage as JPG images since they are automatically converted. Third-party apps or computer programs can still have difficulties interpreting HEIC files though. Luckily, you can disable saving images as HEIC on a iOS 11 device by going to Settings > Camera > Formats > Most Compatible, which will force iOS 11 to save images in the JPEG format.