An HEIC file contains one or more images saved in the High Efficiency Image Format (HEIF), a file format commonly used to store photos on mobile devices. It may contain a single image or a sequence of images along with metadata that describe each image. The file extension ".heic" is most commonly used, but HEIC files may also appear as .HEIF files.

HEIC file open in Apple Preview 10 HEIF, also known as H.265, has become a popular storage format for digital photos because it allows images to be created with a smaller file size while maintaining or improving image quality over JPEG. When Apple released iOS 11 and macOS High Sierra in 2017, the format became the standard for storing photos on iOS devices. Android 9 Pie introduced native support for HEIF images as well. Apple was first to introduce native desktop support for HEIF with High Sierra (macOS 10.13). Microsoft also introduced support with the release of Windows 10 1803 in April of 2018, as long as the Microsoft HEIF Image Extensions from the Microsoft Store is installed. There are several software applications that support viewing and converting HEIC images as well, including File Viewer Plus for Windows, which can both view and convert HEIC images, and iMazing HEIC Converter for macOS. If you are using an iPhone and share an HEIC image with a non-iOS user or a social media site, the image may automatically be converted to JPEG so that it is compatible with the target platform. If you do not want this behavior, or if you would like to continue and use JPEG for saving images rather than HEIF in iOS, open the "Settings" app in iOS, select Camera → Formats → Most Compatible, and choose Most Compatible. NOTE: Some digital cameras also save images in the HEIC format.