Convexy

How to convert HEIC to PNG on iPhone

PNG is the right choice when you need transparency or a format that never degrades again through further edits. It is the wrong choice for an ordinary photo you just want to email — that job belongs to JPG.

The two formats, honestly

HEIC is a HEIF container wrapping an HEVC-encoded image — Apple's camera default since iOS 11. It is lossy, extremely efficient, and holds 10-bit colour plus extras like depth maps.

PNG is a lossless format from the mid-90s built for graphics: screenshots, logos, UI, line art, anything with flat colour, sharp edges or an alpha channel. It uses DEFLATE compression, which throws away nothing — every pixel comes back exactly as it went in.

That is the whole trade. PNG guarantees no further degradation; it does not, and cannot, undo degradation that already happened.

PNG does not restore quality. The HEIC was already compressed with a lossy codec — that information is gone. Converting to PNG faithfully preserves the imperfect pixels you already have, in a much larger file. If someone tells you converting to PNG “improves” a photo, they are wrong.

Expect the file to get dramatically bigger

This surprises people, so plan for it. A 2 MB HEIC photo can easily become a 10–20 MB PNG. PNG's lossless compression is very good at flat colour and repeated patterns, and very bad at photographic noise — every grain of sensor noise is real data it must preserve exactly. A 12-megapixel photo has a lot of noise.

Rule of thumb: for a photograph, PNG is close to the worst format you can pick for size. For a screenshot or a graphic, PNG is often smaller than JPG and looks better too, because JPG's ringing artefacts cluster around hard edges and text.

So when is HEIC to PNG actually right?

If none of those apply and you just need a universally readable photo, convert to JPG instead and save yourself an order of magnitude in file size.

PNG has no quality slider — by design. Convexy shows a quality slider for JPG, HEIC, WebP and AVIF because those are lossy codecs with a rate/quality dial. PNG is lossless, so there is no such dial to offer. To make a PNG smaller, reduce its pixel dimensions with the resize option, or pick a lossy format.

What carries over

The full-resolution pixels come across as they are. Live Photo motion, depth maps and HDR gain maps do not — those live in HEIC-specific boxes that a PNG has nowhere to store. Metadata (EXIF, GPS, IPTC) is stripped by default in Convexy; turn that off in Options if you need it kept. All of this happens on your device, using Apple's imaging frameworks — the photo is never uploaded anywhere, because there is no server to upload it to.

How to do it

  1. Pick the HEIC

    Tap Browse files or choose from Photos, or share a photo into Convexy from another app.

  2. Choose PNG

    Only formats a HEIC can genuinely become are offered. Tap PNG.

  3. Resize if the size matters

    There is no quality slider for PNG — it is lossless. If the output is too large, set a maximum dimension in Options; the image is scaled down proportionally with high-quality interpolation.

  4. Convert

    The result screen shows the original size next to the new one. Do not be alarmed when the PNG is several times larger — that is PNG working correctly on a photograph.

  5. Save or share

    Save to Files or Photos, rename the output if you like, or push it straight into another app from the share sheet.

Common questions

Is PNG better quality than HEIC?

No — it is lossless, which is a different thing. PNG preserves whatever pixels it is handed, perfectly. But the HEIC it was handed had already been through a lossy codec. You get a perfect copy of an imperfect image. PNG only wins on quality when you are going to make further edits, because it stops any additional loss from accumulating.

Why is my PNG so much bigger than the HEIC?

Because HEIC throws information away to get small, and PNG refuses to throw anything away. Photographic detail and sensor noise are effectively random, and lossless compression cannot compress randomness. A 2 MB HEIC becoming a 15 MB PNG is completely normal and is not a bug.

Should I use PNG or JPG for iPhone photos?

JPG, almost always. It is universally readable and a fraction of the size for photographic content. Choose PNG only when you need transparency, a lossless intermediate for editing, or when a specific tool insists on it. For screenshots and graphics, PNG is genuinely the better format.

Does PNG keep transparency from a HEIC?

If the source HEIC actually has an alpha channel, yes — PNG carries alpha natively and nothing is flattened. Photos straight from the iPhone camera have no transparency to preserve. Note that if you converted that same HEIC to JPG instead, any transparency would be flattened onto a solid background, because JPG has no alpha channel at all.

Can I convert PNG back to HEIC?

Yes, and the file will shrink considerably. Just remember it is another lossy encode — it does not recover anything the original HEIC lost, it simply re-compresses the pixels you now have.