Convert HEIC to PNG on Mac

About ten times, and the reason is worth understanding because it decides the whole question.

PNG is lossless. That sounds like an upgrade until you remember what it is being lossless about. A HEIC photo has already been through HEVC compression. The detail it discarded is gone and no format can bring it back. Re-encoding that result as PNG does not recover anything: it just stores the already-compressed picture, including its compression artifacts, one exact pixel at a time.

The last row matters because it closes off the obvious objection. A better PNG encoder does help: Smol’s output was 16% smaller than sips on identical pixels. It is still eight times the HEIC. You cannot optimize your way out of a format choice this wrong.

Scaled up, it stops being an abstraction. A batch of 100 iPhone photos, 120.8 MB of HEIC on disk, became 1.16 GB of PNG. The same 100 files run to JPEG instead came out at 197.6 MB. One untouched 4032 × 3024 frame from an iPhone 15 Pro Max, 1,512,980 bytes as HEIC, came out at 11,189,212 bytes as PNG and 2,439,855 bytes as JPEG.

If your reason for converting is “PNG is the high-quality one”, that is the misconception this page exists to correct. For a photo that is already lossy, PNG buys you exactly nothing and charges you an order of magnitude for it. Convert to JPG instead.

Three routes, all free, all built in. sips is the shortest. It takes a list of files and an output directory, and fixes the extension for you:

mkdir -p png
sips -s format png *.heic --out png/

It prints Warning: Output file suffix changed to png once per file, then echoes each output path still wearing a .heic extension. Both are cosmetic. The exit code is 0 and the folder contains .png files.

Preview gives you the same conversion with a dialog. Open the HEIC, choose File → Export As…, pick PNG from the Format menu, save. With several files open at once and multiple thumbnails selected, that menu item changes to Export Selected Images… and converts the lot in one pass. The export panel gives you Format, Resolution and an Alpha checkbox. There is no quality decision to make here: PNG is lossless, so there is nothing to trade away.

Automator covers the Finder right-click case. Build a Quick Action containing Change Type of Images set to PNG. One serious warning: that action converts in place and deletes the originals. When you drag it in, Automator offers to add a Copy Finder Items action first. Accept.

For folders of hundreds of files, including how the free routes compare on wall-clock time and what happens to capture dates and HDR gain maps, the batch HEIC guide covers all of it with timings. Everything there applies identically to PNG, minus the speed.

When the content is not a photograph. PNG’s compression works by finding runs and patterns of identical pixels, which is exactly what flat fills, hard edges, solid backgrounds and rendered type are made of, and exactly what a photograph has none of.

Four cases where PNG is correct:

• Screenshots and UI captures. Sharp text and flat panels. PNG keeps letterforms crisp where JPEG rings faintly around every edge.
• Logos, icons, diagrams, charts. Large flat areas compress well and edges stay clean.
• Anything with transparency. JPEG has no alpha channel at all. If the source genuinely has one, PNG is the only common destination.
• Design handoff. A file that will be re-edited, layered, or re-exported should not pick up another generation of lossy compression on the way in.

Here is the trap inside that fourth case, measured. Nine macOS screenshots, originally 4.31 MB of PNG, were converted to HEIC and then back to PNG:

The round trip produced a PNG 45% larger than the original, carrying HEVC artifacts it did not have before. PNG is only lossless going forward. Once the content has been through a lossy encoder, converting back to PNG preserves the damage at full price. If you have the pre-HEIC original, use it.

No, and this is the second most common reason people arrive here. Transparency is not a property PNG adds; it is a property the source either has or does not.

Checked on an iPhone camera HEIC: hasAlpha: no, samplesPerPixel: 3. A camera records light hitting a sensor. There is no region of the frame that is “nothing”. Convert it to PNG and you get a three-channel RGB PNG with no alpha channel at all, which we confirmed on every file in the test set.

HEIC itself does support alpha, so a HEIC exported from a design tool with a transparent background will carry that through to PNG correctly. Preview’s Alpha checkbox in the export panel controls whether it is written. What you cannot do is create transparency that was never there. Removing a background is a separate editing job, not a conversion setting.

What does survive the conversion, verified with ExifTool: the capture date, camera make and model, lens, aperture, ISO, GPS coordinates and the Display P3 color profile. All of it is written into the PNG. If you are converting photos in order to publish or share them, that GPS tag is still in the file and stripping it is a separate step.

Because PNG’s DEFLATE pass has to chew through roughly ten times as much output data, and photographic noise is the worst possible input for it.

Eleven times slower per file, for a result nobody can distinguish, and nearly six times the bytes. Feeding a whole camera roll through this is a coffee break and a chunk of your disk. Budget for it, or reconsider the format.

One thing that does help if you are stuck with PNG: shrink the pixels. A 12-megapixel photo does not need to arrive at full resolution for most PNG use cases, and -Z caps the long edge in the same pass:

sips -s format png -Z 2048 *.heic --out png/

For one file, use Preview. It is installed, it is three clicks, and PNG has no quality setting to get wrong. There is nothing an app can add to that transaction.

For a script, use sips. One line, no dependency, same encoder. A build step that needs PNGs out of HEIC should not open a GUI.

If the answer was supposed to be JPEG, go do that instead. Most people who search for HEIC to PNG want a file that opens anywhere, and JPEG does that at a sixth of the size. Our step-by-step HEIC to JPEG guide is the shorter path, and why your iPhone shoots HEIC at all explains whether you needed to convert in the first place.

Smol is worth the $29 when PNG is genuinely the right target and the job is recurring: a folder of screenshots or exported design assets that needs converting, resizing, and squeezing down before it ships. Its PNG output was 16% smaller than sips on identical pixels, which is real money on a site’s image budget, and the Finder Quick Action means no Terminal. It also converts straight to WebP and AVIF, which for anything web-facing beats PNG by a wide margin on both counts. If the underlying problem is a file too large to send rather than a format that will not open, the operation you want is compression rather than conversion, and Smol is a one-time purchase that runs entirely on your Mac.