Converting HEIC to JPG: the iPhone photo format explained

A painter in Lucerne photographs every finished job: the wall afterwards, the state before, and the paint supplier’s invoice. He sends the photos to his bookkeeper. She works on a Windows computer, and some of the files will not open there. They are called IMG_4812.HEIC.

The format is not exotic. It is what newer iPhones save by default. That it does not open everywhere has to do with codecs, licences and the web — and it can be solved.

What HEIC is

Since iOS 11 and macOS High Sierra, Apple has supported two media formats it describes as industry standards: HEIF (High Efficiency Image File Format) for photos and HEVC (High Efficiency Video Coding, also H.265) for video. According to Apple, HEIF and HEVC offer better compression than JPEG and H.264; the files take up less storage at the same visual quality.

Microsoft describes the structure in more detail in its documentation on the HEIF codec: HEIF is a container, similar to TIFF, that can use different compression methods. The default method is HEVC, and such files usually carry the extension .heic. If the AV1 codec is used instead, the file is usually called .avif.

Strictly speaking, then, HEIC is a HEIF image with HEVC compression. In everyday use the terms are often mixed up.

Which devices save HEIC

Apple lists the devices that can capture photos in HEIF, including the iPhone 7 and later models and newer iPads. On Macs running macOS Tahoe 26, Apple says screenshots are also saved as HEIF when the capture format in the Screenshot app is set to HDR. HEIC is therefore no longer just a camera topic.

Format	Compression	Typical use
HEIC	lossy, more efficient than JPEG according to Apple	Photos on iPhone and iPad
JPG	lossy	Photos, readable almost everywhere
PNG	lossless	Graphics, screenshots, transparency
WebP	lossy or lossless	Images on websites

The details on JPG, PNG and WebP come from MDN’s guide, which describes JPEG as the currently most popular format for lossy still images and recommends PNG where more precise reproduction or transparency is needed.

Why HEIC does not open everywhere

On Windows. For HEIF, Microsoft refers to the “HEIF Image Extension” in the Microsoft Store. HEIC files also need the HEVC codec, and Microsoft notes that the HEVC and AV1 codecs may not be available on every PC. That is exactly what the bookkeeper in Lucerne experiences: without these extensions, her computer cannot show the file.

On the web. MDN’s guide to image formats lists APNG, AVIF, GIF, JPEG, PNG, SVG and WebP as the formats most commonly used on the web. HEIC is not among them. Anyone who wants to put an iPhone photo on a website usually needs a different format.

In portals and forms. Many online forms only accept certain formats. The tax administration of the canton of Bern, for example, lists PDF, PNG and JPG for uploading receipts. A HEIC photo has to be converted first.

When the iPhone converts on its own

Not every iPhone photo arrives as HEIC. Apple describes several cases in which it is converted automatically:

• When sharing via AirDrop, Messages or email, media may be shared in a more compatible format such as JPEG if the receiving device does not support the newer format.
• When importing to a PC over USB, media may be converted to JPEG. If you do not want that, set “Keep Originals” on the iPhone under Settings › Apps › Photos.
• When sharing via iCloud Photos, the original format is kept.

That explains why the same person sometimes sends HEIC and sometimes JPG files: it depends on the route, not the photo.

Converting: three ways

On a Mac. Apple describes opening a HEIF image in Photos or Preview, choosing File › Export and selecting a format such as JPEG or PNG before saving. According to its user guide, Preview supports HEIC, JPEG, PNG, TIFF and PDF, among others.

On the iPhone, for future photos. Under Settings › Camera › Formats you can choose “Most Compatible”. According to Apple, new photos are then saved as JPEG. The price is more storage per photo; “High Efficiency” switches back.

On Windows. With the HEIF Image Extension and the HEVC codec, HEIC files can be opened and saved in another format from an image app.

And the videos?

What HEIF is for photos, HEVC is for video. Here too Apple describes how to convert on a Mac: open the video in QuickTime Player, choose File › Export As and, in the dialog, switch from “Smaller File Size (HEVC)” to “Greater Compatibility (H.264)”. According to Apple, resolutions up to 1080p and frame rates up to 60 fps are broadly compatible with older devices; anyone sharing videos that should play everywhere can set the iPhone’s recording accordingly.

What comes along when converting

A photo contains more than pixels. Microsoft mentions in its documentation that HEIF images can contain Exif or XMP metadata from which, for example, the camera model can be read. For many photos these details also include the date taken and, if location services were on, where the photo was taken.

Whether such metadata survives conversion to JPG depends on the program. For the bookkeeper, where the invoice was photographed does not matter. For a photo that ends up on a website or in a listing, it can matter more than one might think — especially if it was taken at home.

Does a photo lose quality when converted?

HEIC and JPG are both lossy: when saving, they leave out image information the eye hardly misses. Converting HEIC to JPG therefore recalculates the image. At a high quality setting the difference is usually barely visible; the file is often larger than the HEIC original, because JPG compresses less efficiently.

PNG is different. Because PNG saves losslessly, everything that was in the HEIC image is kept — with the result that PNG files of photos can become very large. For photos, PNG is therefore rarely the best choice; for screenshots with text, it often is.

For everyday use

The painter and his bookkeeper have two simple options: either he sets “Most Compatible” on the iPhone, or the photos are converted to JPG before they are sent. Both work. What matters is that both know which route applies.

The image tools we are building will convert JPG, PNG, WebP and HEIC into one another and, before download, show which metadata an image contains — and remove it on request. The app will process images in Switzerland, in memory, without any image being kept.