Convert HEIF to PNG

PNG is lossless, and that word does real work in one direction and none at all in the other. Forward, it is a guarantee: the PNG holds the exact pixel values the HEIF decoder produced, and you can open it, save it, copy it and save it again without any of them changing. That is the property an editing workflow needs and the one JPEG cannot offer.

Backward, it promises nothing. The camera already discarded information when it compressed the photograph into HEIF, and no target format can put it back. A lossless copy of a lossy original is exactly that — a faithful copy of what survived. Anyone selling you the other reading is selling something.

This is the page for somebody who is going to work on the picture. You are annotating it, masking part of it, pasting it into a layout, feeding it to a build step that hashes its input, or handing it to a tool whose documentation says it will not accept JPEG. In all of those, a format that changes the pixels every time it is written is a liability.

If instead you simply need the photograph to open on a machine that refuses HEIF — an upload form, a mail client, somebody else's laptop — JPG is the better answer and there is a separate page for it. Sending a 22 MB PNG where a 2 MB JPG would have done is a decision people regret at the other end of a mobile connection.

A compressor that is not allowed to discard anything can only find repetition, and a photograph has very little. Sensor noise, film-like grain, the fine texture of fabric or foliage: to a lossless coder these are close to random data, and random data does not compress. HEIF, allowed to throw the least important of it away, gets the same picture into a fraction of the space.

Ten times the bytes is a fair expectation for a phone photograph, and it is not a sign that something went wrong. Where PNG genuinely wins on size is the other kind of image — flat colour, sharp edges, screenshots, diagrams, line art — and a file with a .heif extension is very rarely one of those.

The encoder alone leaves a great deal on the table, so every PNG written here is passed through oxipng at level 2 afterwards. Measured on a 960 by 640 photograph during development: 1,366 KB straight out of the encoder, 468 KB after the optimiser — two thirds of the file gone, for 464 milliseconds of work.

Level 3 was tried and rejected: it costs 1,133 milliseconds and saves essentially nothing further. Half a second is a real cost and it is the right trade, because the file is the thing you are waiting for and two thirds fewer bytes is worth more than the wait it saves.

Every lossy target on this site offers a quality figure. This pair does not, because PNG has no lossy mode to point it at — the format either stores the pixels or it is not PNG. A setting that appeared here would be decorative.

The one size control that exists is the maximum width. That is not compression, it is fewer pixels, and it is the honest lever: the height comes down with the width, so a 4,032-pixel photograph reduced to 1,600 pixels wide is a sixth of the data before the encoder starts, and the result is still larger than most things need. Leave it at zero to keep the original dimensions.

HEIF is specified with alpha, and so is PNG, so transparency makes the trip. If the file holds a subject on a cleared background — a product shot, an exported graphic, a sticker somebody sent you — the transparent areas stay transparent and nothing is filled in behind them.

This is the single practical reason to prefer PNG over JPG for a HEIF source. JPEG has no alpha channel at all, so the same file converted that way arrives with white behind the subject and no way to remove it afterwards without cutting it out again by hand.

PNG is specified up to sixteen bits per channel, which is more than the ten HEIF can hold, so on paper this conversion has room to spare. In practice the pipeline moves the picture through an eight-bit buffer, so eight bits per channel is what the encoder receives and eight is what lands in the file.

The consequence is narrow but worth stating: a wide-gamut HEIF with a long, smooth gradient can pick up faint banding that was not in the original, and a PNG with sixteen-bit depth would have avoided it. For anything short of a graded studio backdrop, nobody will find the difference.

The PNG that comes out carries pixels and nothing else — no colour profile, no camera model, no capture time, and no GPS position. That is not a privacy feature bolted on afterwards; it falls out of how the conversion works, since decoding to raw pixels and re-encoding leaves no path for a metadata block to travel along.

It is worth knowing in both directions. A photograph you are about to publish is stripped of the coordinates of the place it was taken, which is usually a house. A photograph you are archiving loses its date, so if that mattered, read it off the HEIF before you convert and write it down somewhere that is not the file.

HEIF is a container specification and a single file may hold more than one picture — a burst, a set of alternates, a sequence. The decoder takes the primary image, which is the one any viewer shows you when you open the file, and converts that.

For an editing workflow this is what you want: one file in, one PNG out, no surprise batch of eight images with names you did not choose. Where a container genuinely holds several pictures you care about, that is a job for software built to browse it rather than for a converter.

Both halves — the HEIF decoder and the PNG encoder — execute in the browser tab. Nothing is uploaded, nothing is queued, and there is no server-side copy with a retention policy to read. The free tier accepts files up to 100 MB each, and PNG output is where that ceiling is worth remembering, since the output is much larger than the input.

A folder converts in one pass with a progress row per file, and an "all as ZIP" button appears once two have finished. That is a practical difference for this pair in particular: PNG downloads are large, and thirty of them individually is a slower afternoon than one archive.

Everything above is about a photograph, because that is what a .heif file usually holds. PNG's real strengths lie elsewhere: flat colour, hard edges, text, diagrams, line art and screenshots. On those it is both smaller than a lossy format at equivalent legibility and free of the soft halos that lossy compression leaves around type.

It comes up more often than you would think with this source. Phones save screenshots and scanned documents into the same container as photographs, so a .heif can easily hold a receipt, a chart or a page of text. If that is what you have, PNG is not the expensive lossless option — it is the correct one, and the JPG would have looked worse at a similar size.

Because every output is many times its input, a folder conversion has a footprint worth thinking about in advance. Fifty phone photographs occupying 120 MB as HEIF can land as well over a gigabyte of PNG, all of it written by the browser to your downloads folder in one go.

The free tier's 100 MB ceiling applies per input file, so it will never stop you here — no HEIF approaches it. The limits you will actually meet are your own disk and, on a machine with little memory, the browser holding several decoded images at once. Converting in batches of ten rather than a hundred is the practical answer, and taking each batch as a ZIP keeps the downloads folder navigable.