Convert HEIC to PNG
The photo your iPhone saved, in a format every piece of software on earth will open.
Checking what this browser can decode…
PNG keeps every pixel exactly as it is, so a full-resolution phone photo comes back somewhere between 15 and 40 MB. Choosing a smaller side first is usually the difference between a file you can actually use and one nothing will accept.
PNG is the safe choice, and the expensive one
PNG has the widest support of any image format still in use. Software from 1998 opens it, every operating system previews it, no upload form rejects the extension, and it carries an alpha channel. That is the entire reason to convert a HEIC into one.
The cost is size. PNG is lossless: it stores every pixel exactly, with no discarding of detail. A 12-megapixel iPhone photo occupies about 2 MB as HEIC and somewhere between 15 and 40 MB as PNG, depending on how much fine texture is in the frame. Photographs are the worst case for PNG's compression, because grass, skin and sky have no repeating patterns for it to exploit. If you were converting to get a smaller file, this is the wrong direction entirely — HEIC to JPG is what you want.
When PNG genuinely is the right output
Three cases justify the bytes. The first is anything with sharp edges rather than photographic texture: a screenshot taken on an iPhone, a scanned form, a whiteboard, a receipt. PNG compresses flat regions and hard lines extremely well, and JPEG blurs exactly those.
The second is anything that will be edited and re-saved several times. Every JPEG save discards a little more; PNG survives fifty round trips unchanged. The third is transparency — some HEIC files from iOS 16 onwards, particularly ones produced by the Photos app's subject-lifting feature, carry an alpha channel that JPEG has nowhere to put.
What the resize option does, and why it is there
Choosing a longest side scales the image down before encoding. It is a genuine resize, done with high-quality smoothing, not a display trick — and it is the only effective way to control a PNG's size, because unlike JPEG there is no quality dial to turn.
2048 px is enough to fill any laptop screen and prints acceptably at postcard size. 1024 px suits documentation, tickets and web use. 512 px is avatar territory. Leave it on Original when you are archiving or when a form has told you a minimum resolution.
What does not survive the conversion
A HEIC from an iPhone is a container, not just an image. It may hold a depth map, the short video clip behind a Live Photo, an HDR gain map, burst frames and camera metadata. The conversion takes the still frame the browser hands it and writes that. The rest is dropped, because PNG has nowhere to keep it. If those matter, keep the original HEIC alongside the PNG rather than replacing it.
Common questions
Why is the PNG so much bigger than the HEIC?
Because PNG throws nothing away. HEIC uses modern lossy compression and typically stores a photo in about a tenth of the space PNG needs for the same pixels. A ten-to-twentyfold increase is normal and is not a fault.
Should I be converting to JPG instead?
For an ordinary photograph, almost certainly yes — it will be a fraction of the size and no one will see the difference. Choose PNG for screenshots, scans, diagrams, anything with transparency, and anything you will edit repeatedly.
Why does it say my browser cannot decode HEIC?
Because it has no HEIC decoder. Safari on macOS and iOS uses the system one and works immediately. Chrome, Firefox and Edge on Windows generally do not ship one, and this page tells you so rather than handing you a broken file.
Does the transparency in my HEIC survive?
Yes, where the browser exposes it. PNG has a full alpha channel, so a HEIC that carries transparency keeps it here — which is one of the few clear advantages PNG has over JPG for this conversion.
Can I convert a whole album at once?
Yes. Drop as many files as you like; each is decoded, converted and given its own download button, keeping the original filename with a .png extension.
Is anything uploaded while this runs?
No. Decoding and encoding both happen in this page through the Canvas API. Load the page, disconnect from the internet, and the conversion still works — that is the simplest way to verify the claim yourself.