HEIC vs JPG: which one, and when

If you own an iPhone made after 2017, your photos are HEIC files, and you probably found out the first time you emailed one to somebody who could not open it.

The format is not a mistake. It is genuinely better technology than JPEG by almost every technical measure. It is also worse at the one thing that matters most in practice, which is opening.

What HEIC actually is

HEIC stands for High Efficiency Image Container, and the name is doing something specific: it is a container, not a codec. The container is ISO Base Media File Format — the same structure that MP4 uses. What is inside is a still frame compressed with HEVC, also known as H.265, the video codec.

That is the trick. Video codecs have had far more research investment than still image codecs over the last twenty years, because streaming is a much larger industry than photography. HEVC contains prediction techniques that JPEG’s 1992 design simply does not have: it can predict blocks from neighbouring blocks in 35 different directions, use variable block sizes from 4×4 to 64×64, and apply a deblocking filter to hide the block boundaries that make heavily compressed JPEGs look like mosaics.

The result, in practice, is that a HEIC file is roughly half the size of a JPEG that looks the same. On a 256 GB phone that is thousands of extra photographs.

The container also carries things a JPEG cannot: depth maps for portrait mode, the frames of a burst, the short video clip attached to a Live Photo, multiple images with different exposures, and an alpha channel.

What JPEG has that HEIC does not

Thirty-four years of ubiquity.

Every operating system, every browser, every printer, every photo kiosk, every web form, every programming language’s standard image library, every ancient piece of enterprise software still running in a government office — all of them read JPEG. There is no negotiation and no codec pack.

HEIC’s support is narrower and more complicated than it first appears:

• Apple devices handle it natively and always have.
• Windows 10 and 11 need the HEIF Image Extensions from the Microsoft Store, and on many machines the HEVC Video Extensions too, which historically cost money.
• Android has supported HEIF since version 10, but individual apps vary.
• Browsers, with the exception of Safari, generally do not display HEIC at all.
• Web upload forms overwhelmingly accept JPG and PNG only. A HEIC upload is rejected, usually with an unhelpful error.

The last one is where most people meet the problem. Visa portals, university applications, job boards, insurance claims and tax filings do not care that your format is more efficient.

The patent situation

There is a reason browser vendors have been reluctant, and it is not technical.

HEVC is covered by patents held by several separate licensing pools. Anyone shipping an HEVC decoder to a large number of users may owe royalties, and the terms have historically been complicated enough that companies with a lot to lose have simply not shipped it. Apple pays; browser vendors mostly have not.

This is exactly the problem AV1 — and therefore AVIF — was created to solve. AV1 was designed by a consortium including Google, Mozilla, Microsoft, Netflix and Amazon specifically to be royalty-free, which is why AVIF support arrived in browsers far faster than HEIC ever did.

When to keep HEIC

• Photos staying inside the Apple ecosystem. iPhone to iPad to Mac to iCloud, nothing to change.
• Storage-constrained devices. Half the size is half the size.
• Portrait mode, Live Photos and bursts, where the extra data in the container is the point.

When to convert to JPG

• Anything going to someone on Windows or Android.
• Any web form, application portal or government submission.
• Any print service, unless you have confirmed they accept it.
• Long-term archives, where you want a format that will certainly still open in twenty years.
• Anything you will edit in older software.

The HEIC to JPG converter here does the conversion in your browser — which matters more than it might sound, because the photos people most often need to convert are photographs of identity documents.

What conversion costs you

Both formats are lossy, so converting is a re-encode and some information is discarded. How much depends on the quality setting:

Quality	12 MP photo	Visible difference
100	4–6 MB	none, and wasteful
90	1.5–2.5 MB	none at normal viewing size
80	0.8–1.4 MB	none unless you zoom in
70	0.5–0.9 MB	faint softening in fine detail

Quality 90 is the right default for anything you might print or edit later. Quality 80 is indistinguishable for email and web use.

There is one thing worth deciding consciously: metadata. A HEIC straight from a phone carries the GPS coordinates of where it was taken, to about a metre. Converting drops that by default here, which is usually what you want — but if you are archiving family photos, the date and location are part of what makes them worth keeping. The checkbox is there.

A third option

If the destination is your own website rather than someone else’s form, neither format is the right answer. WebP is smaller than JPEG, universally supported in browsers, and does transparency. AVIF is smaller still.

The image converter handles all of these, and the format-pair pages explain what each conversion trades away.