HEIC → PNG

How offline HEIC to PNG conversion works

This page is a static HTML document with a WebAssembly library (libheif) embedded into it. When you drop a HEIC file, the file is read into your browser's memory using the FileReader API, decoded by the WASM module on your CPU, re-encoded as PNG, and handed back to you as a download. At no point does the file leave your device.

Why convert HEIC to PNG?

HEIC is Apple's preferred format since iOS 11 — files are about 50% smaller than equivalent JPGs, which is great for storage on your phone. But when you need to work with those photos, the right output format depends on what you're doing. PNG is the right choice when:

• You're editing the photo — PNG is lossless, preserving every pixel of the original HEIC for Photoshop, GIMP, Affinity Photo, Lightroom, or Capture One. JPG introduces compression artifacts that accumulate with each edit.
• You need transparency — PNG supports alpha channels. If your HEIC has transparency (rare in standard iPhone photos, common in ProRAW and Live Photos), PNG keeps it. JPG cannot.
• You're preparing for design tools — Figma, Sketch, Adobe XD, Canva, and most design software work best with PNG input for lossless image embedding.
• You're publishing to the web with quality control — PNG is lossless, so images rendered at retina resolutions stay crisp. JPG can introduce banding in gradients.
• You're doing archival or print — PNG is the safest "preserve everything" format. File size matters less than data preservation.

For everyday sharing (email, social media, messaging), JPG is usually better — files are 3-5x smaller. See our HEIC to JPG converter for that workflow.

Why offline conversion matters

Most "free HEIC converter" websites work by uploading your photos to their servers, converting them there, and sending the file back. That's fine for vacation snapshots, but a problem if your HEICs contain:

• Sensitive personal photos (medical, family, intimate)
• Confidential business documents you photographed
• Screenshots of legal or financial information
• Anything you wouldn't want sitting on a stranger's server, even briefly

With offline conversion, the file is processed entirely inside the privacy sandbox of your browser tab. The server hosting this page (Netlify) serves the HTML, CSS, and WASM library, then has nothing else to do — there's no "upload" endpoint on our side because we don't process files server-side.

How to verify it's really offline

You don't have to trust us. Verify it yourself:

1. Open your browser's DevTools (right-click → Inspect, or F12).
2. Switch to the Network tab and clear it.
3. Drop a HEIC file onto the converter above.
4. Watch the Network tab — it stays empty during conversion. No XHR, no fetch, no WebSocket. Nothing.

Alternatively: load this page, then turn off your wifi or unplug your ethernet. The converter still works because everything it needs is already in your browser's memory.

"No upload" is a stricter guarantee than "private"

Lots of HEIC converters call themselves private. Read the fine print and you usually find:

• "Files are deleted after conversion" — meaning they were uploaded first.
• "Encrypted in transit" — meaning they're transmitted, just over HTTPS.
• "We don't store your files" — relying on the operator's promise rather than architecture.
• "GDPR compliant" — a regulatory claim, not a technical one.

All of these still involve your file existing on someone else's server, even briefly. That's a fundamentally different threat model from the file never being transmitted at all.

This converter is the second kind. There is no upload endpoint. There is no server-side process to delete the file from. The architecture itself makes data leakage impossible — not because we promise to be careful, but because there's nothing to be careful with.

HEIC vs PNG — what's the difference?

HEIC (also called HEIF) is Apple's preferred image format since iOS 11. It's based on the modern HEVC video codec and produces files about 50% smaller than equivalent-quality JPGs. Supports both lossy and lossless compression, plus alpha channel. Great for storage on your phone.

PNG (Portable Network Graphics) is the lossless standard from 1996. It's supported by literally every image editor, design tool, and operating system. Files are much larger than HEIC, but every pixel of the original is preserved exactly.

This converter gives you the best of both: keep storing originals as HEIC on your iPhone, convert to PNG on demand when you need to edit or design.

Open architecture for the paranoid

Everything on this page is inspectable:

• The converter library (libheif) is open source — github.com/strukturag/libheif. You can read every line.
• The page itself — right-click → View Source. You'll see plain HTML and the converter JS that wires the drop zone to the engine. No obfuscation, no minified mystery code.
• The network — DevTools shows everything. There are no hidden requests because browsers can't make hidden requests.