What is HEIF?

How HEIF Works

HEIF, the High Efficiency Image File Format, is best understood as a container rather than a single compression method. It defines how images and related data are packaged inside a file, including how items are indexed and referenced, but the actual picture data inside is produced by a separate image codec. This separation is important: HEIF describes the box, and something else fills it.

In the most common case, the images stored inside a HEIF container are coded with HEVC, also known as H.265, which is a modern and efficient video style codec applied to still pictures. When a HEIF file holds HEVC-coded images, it is usually given the .heic extension. This is why the terms HEIF and HEIC are often used loosely, even though HEIF is the general container and HEIC is the common HEVC based case.

The container is flexible enough to hold much more than one picture. A single file can contain an image sequence or burst, a live photo that pairs a still with a short motion clip, a depth map used for portrait style background blur, one or more thumbnails, and alpha or auxiliary channels. It can also record non-destructive edits, so adjustments such as crops or rotations are stored as instructions rather than baked into the pixels.

The practical result is that HEIF files are typically much smaller than JPEG files at a comparable visual quality, because the underlying codec is more efficient, while the container adds capabilities that JPEG never had. This combination of smaller size and richer features is the format's main appeal for modern devices.

History and Standardization

HEIF is an international standard developed within the MPEG standardization effort and published by ISO/IEC as part of the MPEG-H family of specifications. It was defined as a general purpose container for images and image sequences, deliberately designed to be codec agnostic so that different image codecs could be carried inside the same structure.

The format gained mainstream visibility when Apple adopted HEIF, in its HEVC based HEIC form, as the default photo format on its mobile devices starting in 2017. That decision put the format on hundreds of millions of phones and pushed other software to add support for reading and converting it.

Because HEIF itself is a container, its standardization covers the file structure and how items relate to one another, while the image coding relies on separate codec standards such as HEVC. This layered approach is deliberate and mirrors how modern media formats separate packaging from compression.

HEIF Compared to JPEG and AVIF

Against JPEG, HEIF offers clearly better compression efficiency and a far richer feature set, including depth maps, image sequences, and non-destructive edits. The cost is compatibility: JPEG is understood by essentially every device and application in existence, while HEIF and HEIC still require reasonably modern software or explicit conversion to open everywhere.

Against AVIF, the comparison is closer. AVIF uses images coded with the AV1 codec and shares many of the same container ideas about storing efficient still images. A key practical difference is licensing: AV1 is designed to be royalty free, whereas the HEVC codec that HEIC relies on is subject to patent licensing, which has been a real source of friction for adoption.

The honest trade off is that HEIF and HEIC deliver excellent quality per byte and are deeply integrated into a major mobile ecosystem, but their reliance on HEVC licensing complicates universal support. AVIF avoids that licensing concern, while JPEG remains the safe choice when maximum compatibility matters more than file size or advanced features.