Explainer · 4 min read
Your iPhone didn't pick HEIC to annoy Windows users, even if it feels that way. It picked it to save space. Here's the reasoning, and the times your phone quietly converts to JPG on your behalf.
Updated
Need a few iPhone photos as JPGs right now? Use the converter on this page. On iPhone, pick photos from your library, convert them, then tap Save to put the JPGs back in Photos. It all happens in Safari on your device, with no upload. If you'd rather your iPhone never made HEIC files at all, skip to changing your camera settings.
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Phone cameras keep getting better, and better cameras make bigger files. Apple's problem in 2017 was simple: people were filling their phones with photos and video, and storage was (and is) the most expensive thing to add to a phone.
HEIC fixed a big part of that. Because it uses HEVC compression, a HEIC photo is typically about half the size of a JPG of the same visual quality. For someone with 20,000 photos, that could mean many gigabytes back without deleting anything. It also means smaller iCloud backups and faster syncing.
Apple announced the move at its developer conference in June 2017 and shipped it in iOS 11 that autumn, alongside macOS High Sierra (10.13). Two things happened together:
Both changes were labelled High Efficiency in the Camera settings, and the old formats became Most Compatible. Capturing in HEIC needs hardware HEVC encoding, so it's the default on iPhones with an A10 Fusion chip or later, which means iPhone 7 onwards.
Because Apple controlled the whole chain on its own devices (camera, Photos app, iCloud, Mac), it could switch formats almost invisibly. The friction only showed up at the edges, where photos met Windows PCs, websites and other people's apps.
Storage was the headline, but HEIC also gave Apple room to grow.
At the same file size, HEIC holds more detail and shows fewer compression artefacts than JPG. Apple could keep photos looking good while still saving space.
HEIF is a container, so a single file can hold the photo plus related data. Apple uses this for:
Live Photos also lean on Apple's ecosystem: the still is a HEIC and the motion is a linked video file, kept together by the Photos app.
JPG is stuck at 8 bits per colour channel. HEIF allows more, which matters for HDR and for smoother gradients. JPG has no clean way to grow into that.
Here's the part most people don't realise: your iPhone already converts HEIC to JPG a lot of the time, behind the scenes. Behaviour varies by iOS version and app, but these are the common cases.
When you share a photo through the Share sheet to an app or service that doesn't declare HEIC support, iOS usually hands it a JPG. Messaging apps and social apps typically receive a compatible version, often resized too.
Attaching photos from the Photos library in Mail usually produces JPGs, and Mail may offer to send a smaller size. Messages between iPhones may keep HEIC, since both ends understand it. See our guide to emailing HEIC photos for the details.
When a website asks you to pick a photo and you choose one from your Photos library, Safari usually converts it to JPG unless the website says it accepts HEIC. That's why uploads from an iPhone often just work. Our guide on uploading iPhone photos to a website covers the cases where they don't.
With a cable, the setting at Settings → Photos → Transfer to Mac or PC decides what you get:
The automatic conversion has gaps, and those gaps are where HEIC files escape:
For most people, yes. The space savings are real, quality is excellent, and the iPhone hides the format most of the time. The occasional HEIC that escapes is easy to fix with a converter.
If those escapes happen constantly (you send a lot of photos to Windows users, or upload to fussy websites every day), switching the camera to Most Compatible may save you more time than it costs in storage. On some models, a few camera features are only available with High Efficiency, so check before you switch. Our iPhone camera settings guide walks through it.
FAQ
Apple switched to HEIC with iOS 11 in 2017, announced alongside macOS High Sierra. iPhones with an A10 Fusion chip or newer, starting with iPhone 7, save photos as HEIC by default.
Screenshots are PNG, and photos received from other people or saved from the web keep their original format. If the camera itself saves JPG, the Camera format is probably set to Most Compatible.
Yes. A HEIC photo is typically about half the size of a JPG of similar quality. Across a large photo library that adds up to many gigabytes.
Often, yes. iOS usually converts when you share to apps and services that can't handle HEIC, when attaching photos in many cases, and when importing to a computer with the Transfer to Mac or PC setting on Automatic.
Only if conversion is a constant hassle. Turning it off makes every photo bigger and, on some models, limits certain camera features. Converting when needed is usually the better trade.
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