What is HEIC?

Three names that get used interchangeably and should not be.

HEIF is the container — a standardised file format that can hold images, sequences and metadata, and is agnostic about how the images inside are encoded.

HEVC, also called H.265, is a video codec.

HEIC is the combination: a HEIF container holding HEVC-encoded still images. That is what an iPhone writes.

The distinction matters because HEIF can hold other codecs — an AVIF file is, technically, a HEIF-derived container holding AV1-encoded images. The container is not the problem; HEVC is.

HEVC is a modern video codec, and it inherits everything that comes with that: variable block sizes, many prediction modes, and sophisticated filtering — a far larger search space than JPEG's fixed 8 × 8 blocks.

Applied to a single still frame, that produces a file roughly half the size of an equivalent JPEG. For a phone taking thousands of photographs, halving storage is a substantial win, which is why Apple switched.

HEVC is encumbered by a complicated patent licensing situation involving multiple pools and licensors. That has made it expensive and legally awkward to implement, particularly for open-source browsers and free software.

It is the direct reason Chrome and Firefox do not decode HEIC, and the reason Windows historically charged for the HEVC extension needed to view iPhone photographs. It is also a large part of why AV1 — and therefore AVIF — was created as a royalty-free alternative.

So HEIC's limited reach is not a technical failure. The format is good. The licensing is what stopped it.

Only if compatibility is a recurring irritation. Settings → Camera → Formats → Most Compatible saves JPEG instead, at roughly double the storage.

Leave it on High Efficiency if you mostly stay within Apple's ecosystem or share through channels that convert automatically. Switch if you regularly move files to Windows machines or upload to systems that reject HEIC.

To convert an existing library: Preview on a Mac exports to JPEG, and Finder's Quick Actions handle batches. On Windows you will need the extensions installed first, or a converter that bundles its own decoder.

These tools use the browser's own codecs, and Chrome and Firefox cannot decode HEIC. A HEIC page would therefore fail for the majority of visitors — silently, on the file they had just chosen.

Supporting it would mean shipping a WebAssembly build of libheif, well over a megabyte, to work around a licensing problem. That is a reasonable thing for a dedicated converter to do; it is not something to imply is already here. Convert on a Mac with Preview, or with desktop software that includes a licensed decoder.