What Are HEIC Files? A Plain Guide

If you have ever emailed a photo from an iPhone and been told the file “won’t open”, you have met HEIC. It is not a broken file and it is not a mistake — it is simply a newer image format than the software on the other end knows about.

The short version

HEIC stands for High Efficiency Image Container. It is the format Apple has used by default for iPhone photos since iOS 11, released in 2017. A HEIC photo is roughly half the size of the same photo as a JPEG, with no visible loss in quality.

That compression is the entire reason it exists. A 12-megapixel photo that would take about 4 MB as a JPEG takes closer to 2 MB as HEIC. Across a few thousand photos, that is the difference between filling your phone and not.

Why it will not open

The format is fine. The problem is support, and support arrived unevenly:

Windows 10 and 11 need a codec from the Microsoft Store before Photos will display HEIC. It is a free download, but it is not installed by default.
Older Android versions cannot display it at all.
Web apps and content management systems frequently reject the file at upload, because their image libraries were written before the format existed.
Email clients vary. Some show a preview; some show a broken icon.

None of this is a defect in your photo. It is a gap between what your phone writes and what the receiving software reads — and it closes a little every year.

HEIC, HEIF and HEVC — three names, one family

These get used interchangeably and they are not the same thing.

HEIF (High Efficiency Image Format) is the underlying standard, developed by the Moving Picture Experts Group. HEIC is Apple’s specific implementation of it — a HEIF container using HEVC compression inside. HEVC, also called H.265, is the video codec doing the actual compression work.

The practical consequence: a .heic file is a HEIF file, but not every HEIF file is a .heic file. In everyday use the distinction almost never matters. When it does — usually when a piece of software claims to support one but not the other — it is worth knowing they are not synonyms.

What a HEIC file can hold that a JPEG cannot

This is the part most explanations skip, and it is why simply renaming the extension never works.

A HEIC file is a container, not a single image. Inside it there can be:

Multiple images in one file — which is how Live Photos and burst shots are stored
A depth map, used for Portrait mode background blur
Image edits stored non-destructively, so the original survives
16-bit colour, where JPEG is limited to 8-bit
Transparency, which JPEG cannot do at all

When you convert a HEIC to JPEG, all of that is flattened. You get the primary image and nothing else. That is usually what you want — but it is worth knowing what you are giving up, particularly with Live Photos, where the motion is discarded silently.

The privacy problem with converting

Most HEIC converters online work by uploading your photo to a server, converting it there, and sending it back. For holiday snaps that is merely inelegant. For photos of documents, children, medical paperwork or anything you would not post publicly, it means handing a copy to a company whose retention policy you have not read.

HEIC photos also carry EXIF metadata — including, by default, the GPS coordinates of where the photo was taken. Uploading the file to convert it means uploading that location too.

There is no technical reason conversion needs a server. The decoding library runs perfectly well in a browser, which means the file never has to leave your device at all — which is how the HEIC to JPG converter here works. On a Mac or an iPhone it does not even download a decoder, because Safari already has one built in. If you need transparency preserved rather than a smaller file, HEIC to PNG is the lossless route.

Should you just turn HEIC off?

You can. On an iPhone: Settings → Camera → Formats → Most Compatible. Your phone will shoot JPEG from then on.

Whether you should depends on what annoys you more. Switching to JPEG roughly doubles the storage every photo takes and loses the 16-bit colour depth — a real cost if you edit your photos. Staying on HEIC means occasionally converting a file before sending it somewhere old.

For most people, staying on HEIC and converting the occasional file is the better trade. The compatibility gap is closing; the storage you spend is gone for good.

There is also a middle path many people miss: AirDrop and Apple’s own Share sheet already convert automatically when the receiving device cannot handle HEIC. If your only problem is sending photos to one Windows-using relative, the conversion may already be happening without you doing anything.

What are HEIC files?