Why Does iPhone Use HEIC Instead of JPG?

Ask most people what format their iPhone photos are in and they’ll say JPEG. Every iPhone since the 7 has been shooting HEIC by default. The gap between those two facts stays invisible until someone moves files to a Windows PC or hits an upload form that rejects the extension, at which point it becomes the only thing they care about.

The decision made sense for Apple. Whether it makes sense for you depends on which side of that upload form you’re standing.

The storage maths

The iPhone 15 Pro shoots 48-megapixel images, and the base model ships with 128 GB that also has to hold the OS, apps, messages and video.

HEIC roughly halves photo file sizes against JPEG. Five thousand photos is the difference between about 15 GB and about 30 GB. Apple cares because people who run out of storage get unhappy in expensive ways. They stop shooting and they ring support. Cutting file sizes in half buys back a chunk of storage that Apple would otherwise have to ship in hardware and eat in margin.

iCloud sharpens the incentive. Smaller photos mean fewer people slamming into the 5 GB free tier and, for those who do pay, more photos fitting under whatever they’re paying for. Every one of those files sits on Apple’s storage bill.

HEVC compresses better, and not marginally

JPEG’s compression method dates from 1992. HEVC, the codec inside HEIC, is a couple of decades younger, and that gap shows up in some very specific places.

JPEG divides an image into fixed 8x8 blocks and treats each one much the same way. HEVC picks block sizes from 4x4 up to 64x64 depending on what’s in the frame — a stretch of flat sky costs almost nothing, while a face gets the fine treatment. It also predicts pixel values from neighbouring blocks far more aggressively than JPEG’s scheme allows, then runs a deblocking filter over the result to clean up the edges that low bitrates leave behind.

The outcome is the same quality at half the size, or noticeably better quality at the same size, depending on which knob you turn. I put together a detailed HEIC vs JPG quality comparison with real file sizes if you want to see it rather than take my word for it.

What the container makes possible

Compression is the boring half of the answer. The interesting half is that HEIC holds more than one thing at a time.

Without that, Live Photos and Portrait Mode would need sidecar files. Every photo you took would produce a second hidden file carrying the video clip or the depth map, and every operation on your library would have to keep the pair together. Copy one without the other and you’d silently lose the effect. Anyone who’s dealt with RAW plus XMP sidecars knows how that goes. Apple got to skip the whole problem by putting everything in one file. The wider colour depth was a bonus, and it gave the computational photography pipeline more room for HDR work.

The silicon was already there

Apple’s A-series chips carry a dedicated media engine for HEVC. Encoding and decoding happens in fixed-function hardware rather than on the CPU, which is why your phone can fire off a burst without the battery noticing.

That’s also why Apple didn’t pick WebP or AVIF. WebP couldn’t do the things Apple needed in 2017, and AVIF wasn’t finalised until 2019. HEVC was already standardised and already sitting in the chip they were shipping anyway. Picking anything else would have meant software encoding on every shutter press.

Is it lock-in?

HEIC creates friction the moment you leave Apple’s world. Files that behave perfectly across iPhone, Mac and iPad hit a wall when you hand them to someone on Windows or upload them somewhere that hasn’t bothered.

Apple isn’t ignoring that. iOS quietly converts to JPEG when you share through email or iMessage to a non-Apple device. Direct transfers are where it stops helping. Pull photos over USB or through iCloud on Windows and you get the raw file.

My read is that it’s a side effect Apple has never been in a hurry to fix rather than a deliberate trap — which amounts to the same thing from where you’re sitting.

Living with it

Converting when you need to leave the ecosystem is the low-effort answer. heic.site does it in your browser, nothing gets uploaded, and the free tier takes three files at a time with no limit on how many batches you run.

Switching the camera to JPEG is the other option, at Settings, Camera, Formats, Most Compatible. You’ll burn storage twice as fast and lose Live Photos. I’d convert.