HEIC to JPG: converting iPhone photos without wrecking them

Every iPhone since 2017 shoots HEIC by default, and every week someone discovers that the photos they airdropped to themselves won't open on their Windows PC, won't upload to a government form, and turn into grey boxes in an old CMS. The fix is a conversion to JPG — which sounds trivial and is, right up until it quietly ruins colour, strips location data you wanted to keep (or keeps data you wanted stripped), or doubles the file size for no visible gain.

Here's what's actually going on, and how to convert without any of that.

Why HEIC exists at all

HEIC is a container (HEIF) holding an image compressed with HEVC — the same codec as 4K video. Against JPEG's 1992-era compression it's simply better maths: at the same visual quality a HEIC file is typically 40–50% smaller, and it supports 10-bit colour, alpha transparency, live photo sequences and auxiliary depth maps. Apple adopted it because camera rolls were eating phones alive.

The catch is licensing and support. HEVC decoding is patent-encumbered, so plenty of software — older Windows, most browsers until recently, a long tail of upload forms and printing kiosks — never learned to open it. JPG opens everywhere, forever. That's the whole reason this conversion exists.

The three ways the conversion goes wrong

1. Quality set blindly

JPEG quality is a 0–100 knob and most tools pick a default without telling you. Too low (a lot of "free converter" sites use ~75 to save bandwidth) and you get blocky skies and smeared skin tones. Too high (100) and you get a file larger than the original HEIC with no visible improvement — quality 100 disables most of the compression that makes JPEG useful.

For photos, quality 85–92 is the practical band. At 90, side-by-side at 100% zoom, almost nobody can spot the difference from the source; the file lands around a third of the size of a quality-100 export.

2. Colour space clipping

Recent iPhones capture in Display P3, a colour space wider than the sRGB most of the web assumes. A naive converter that copies pixel values and ignores the colour profile produces JPGs that look subtly flat and desaturated — reds and greens are the obvious casualties. A correct conversion either embeds the P3 profile in the JPG or converts the pixels to sRGB properly. If your sunset photos look washed out after conversion, this is why.

3. Metadata, both directions

A HEIC from an iPhone carries EXIF: capture time, camera settings, and GPS coordinates of where you were standing. Converters handle this in one of three ways — copy everything, strip everything, or (worst) strip selectively and silently. Both failure modes are real:

• You convert your photo library for archiving and the converter drops the dates — every photo now sorts by conversion day.
• You convert a photo to post publicly and the converter keeps GPS — you've just published your home address.

The right behaviour is a choice, not a default you have to reverse-engineer.

A sane conversion, step by step

1. Decide the destination first. Web upload or sharing: sRGB, quality 85–90, strip GPS. Archive/print: keep the colour profile, quality 92+, keep all metadata.
2. Convert a single test file and check three things: file size is in a plausible range (roughly 1–4 MB for a 12 MP photo), colours match the original on the same screen, and the EXIF is what you intended (exiftool file.jpg if you're on a command line).
3. Then batch the rest with the same settings. Consistency matters more than any individual setting — a library converted at three different quality levels is a mess you can't fix later.

If you'd rather not orchestrate this yourself, this is exactly the boring work MorphTo does: HEIC to JPG server-side with correct colour management, sensible quality defaults, and an explicit keep-or-strip metadata choice — one photo in the browser or thousands through the API.

When not to convert at all

If everything that will ever touch the file is Apple hardware or recent software, leave it as HEIC — it's the better format. Convert when a real consumer of the file can't read it, and when you do, keep the originals. JPG is a one-way door: you can always make a JPG from a HEIC later, but you can't put the discarded information back.