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What Is HEIC? Understanding Apple's Image Format

The C in HEIC stands for container. That single word explains most of what people find confusing about these files, and I only worked it out properly after building a converter that has to handle every variation Apple ships.

A container is not a format

JPEG is a compression method and a file layout welded together. One image goes in, one comes out. Nothing else in the file is worth arguing about. HEIC is a box — High Efficiency Image Container, holding data compressed with HEVC, the same codec that made 4K video small enough to stream. Apple made it the default on every iPhone from iOS 11 onwards in 2017, and there are good reasons they chose it over JPEG.

What sits in the box varies. Usually a single still. It might be a still with a three second clip attached, which is what a Live Photo actually is, or that same still carrying a depth map from Portrait Mode. Bursts pack a whole run of frames into one file with one of them flagged as the keeper. All of it arrives with the same .heic extension.

This is why “does my software support HEIC” has no clean answer. A viewer might open your ordinary snapshots and choke on a burst. That’s not a bug so much as a partial implementation of a spec that’s broader than most people assume.

The size argument

A 12-megapixel photo that lands at 3 to 4 MB as a JPEG comes in nearer 1.5 to 2 MB as HEIC, at quality you’d struggle to tell apart on a phone screen. The full HEIC vs JPG comparison has the numbers.

Halving looks abstract until you apply it to a real phone — ten thousand photos on a 128 GB device that’s also holding apps, messages and a couple of downloaded seasons of something. Apple’s alternative was shipping more storage at their own cost, or watching people run out and blame the hardware, and the iCloud side sharpens it further, since smaller photos mean fewer people pushing past the 5 GB free tier.

The format also gives Apple’s camera software room to work. HEIC carries 16-bit colour, which is a lot more headroom for the HDR processing that happens between you pressing the shutter and the photo appearing. And the A-series chips have a media engine that encodes HEVC in dedicated silicon, so all of this costs almost nothing in battery.

Windows can decode HEVC. It has been able to for years. What it won’t do is ship the decoder for free, because HEVC carries patent licensing that Microsoft chose not to absorb into the price of the OS. So it’s a separate purchase, and there are a few ways round that.

The same licence question sits behind Chrome. It added HEVC video decoding in 2022 and still won’t render a .heic image. Plenty of upload forms and social platforms reject the extension outright.

Apple works around its own format constantly, incidentally. Send a photo through iMessage or email to a non-Apple device and iOS converts it to JPEG before it leaves the phone. Pull the same file off over USB and you get the raw HEIC.

Opening one right now

Drop it into heic.site and it converts in the browser. Nothing is uploaded. Free accounts do three files per batch, returned as a ZIP, with no cap on how many batches you run, and Pro lifts the per-batch limit. For a big library, the batch conversion guide is the faster path.

Turning HEIC off is the other option: Settings, Camera, Formats, Most Compatible. You’ll use roughly twice the storage and lose Live Photos. Most people convert instead.

Support creeps forward each year. But JPEG dates from 1992 and took decades to become genuinely universal. HEIC has a licence attached that JPEG doesn’t. I’d plan on converting for a while yet.