The Problem Every iPhone User Knows Too Well
You've been there. You take a gorgeous photo on your iPhone, try to email it to a colleague on Windows, and they reply: "I can't open this .heic file." Or you try uploading a photo to a job application, a school portal, or a printing service — and the form just rejects it.
Since 2017, every iPhone running iOS 11 or later saves photos in HEIC (High Efficiency Image Container). It's a brilliant format — your photos take up roughly half the space of a JPG at the same visual quality. The catch? Almost nothing outside the Apple ecosystem supports it.
What Exactly Is HEIC?
HEIC stands for High Efficiency Image Container. Inside it sits an image compressed with HEVC (H.265) — the same codec that made 4K video streaming practical.
You'll also hear HEIF (High Efficiency Image File Format). HEIF is the container standard, defined by ISO/IEC 23008-12. HEIC is what you get when that container holds HEVC-compressed pictures — which is exactly what your iPhone creates. In everyday use, the two terms are interchangeable.
Why Apple Chose HEIC
One word: storage. A 128 GB phone can hold thousands of extra photos thanks to HEIC. In our tests, a 287 KB HEIC file became a 581 KB JPG at quality 90 — double the space for the exact same photo.
The Advantages
- 🗜️ ~50% smaller than JPG at the same visual quality
- 🎨 10-bit colour — smoother gradients, less banding in sunsets
- 🔲 Supports transparency (JPG cannot)
- 📸 Stores Live Photos, bursts, and Portrait depth maps in one file
- ✏️ Non-destructive edits — crops and adjustments can be undone
- ⚡ Hardware-decoded on Apple devices — fast and battery-friendly
The Problem
- ❌ Windows needs an extra extension from the Microsoft Store
- ❌ No browser except Safari will display a .heic file
- ❌ Most upload forms reject it outright
- ❌ Older printers, TVs, and photo kiosks can't read it
- ❌ Patent licensing keeps support out of many free/open-source tools
- ❌ Sharing with Android or Windows users almost always requires conversion
The Solution: Convert in Your Browser, No Upload Required
I've been using Resizo's HEIC to JPG Converter and it solves this elegantly.
The key differentiator? Your photos are never uploaded to any server. Everything happens inside your browser tab.
How It Works — 4 Simple Steps
- Drop your HEIC files onto the page (or browse your photo library)
- Pick your output format — JPG, PNG, WebP, AVIF, GIF, BMP, TIFF, ICO, or PDF
- Hit Convert — decoding runs on a background thread so the page never freezes
- Download — save individually or grab everything as a ZIP
10 Output Formats
This isn't your typical "HEIC to JPG" tool. You get ten formats:
| Format | Type | Best For |
|---|---|---|
| JPG | Lossy | Universal sharing — works everywhere |
| PNG | Lossless | Editing, transparency, master copies |
| WebP | Lossy/Lossless | Web — 25-35% smaller than JPG |
| AVIF | Lossy | Web — ~30% smaller than JPG |
| GIF | 256 colours | Simple icons and graphics |
| BMP | Uncompressed | Legacy compatibility |
| TIFF | Lossless | Professional printing |
| ICO | Multi-resolution | Website favicons |
| Document | Merge multiple photos into one file |
Pro tip: At the default quality of 90, every full-size format comes out bigger than the HEIC you started with. That's not a bug — HEIC uses much newer compression. If matching the original size matters, choose AVIF and pull quality down to ~70.
Privacy: Why It Actually Matters
Most online converters work like this:
- You upload your photo to their server
- Their server converts it
- They promise to delete it "after one hour"
Resizo works differently:
Your photos are never transmitted. The decoder and encoders run inside your browser tab. Close the tab and everything is gone from memory — nothing was ever written to anyone's disk.
Don't Take My Word for It — Verify It Yourself
- Load the page
- Turn on airplane mode or disconnect from Wi-Fi
- Add a HEIC file and convert it
- It still works — because there's no server to phone home to
Or open DevTools → Network tab and watch: zero image requests are ever made.
EXIF Metadata Gets Stripped
Conversion decodes your photo to raw pixels and writes a fresh file. EXIF metadata — GPS coordinates, camera model, serial number, timestamps — does not carry across. If you're about to post a photo of your home publicly, that's a meaningful privacy win.
Browser Sandbox Security
Conversion runs inside the browser's sandbox, which can't reach your file system beyond the files you explicitly chose. The HEIC decoder is a WebAssembly module — memory-isolated by design, unable to make network requests on its own.
Platform-by-Platform Guide
📱 iPhone & iPad
Open the page in Safari or Chrome, tap the drop area, and pick photos from your library. iOS decodes HEIC natively, so conversion is especially fast — the WebAssembly decoder never even downloads.
🍎 Mac
Preview and Photos can export to JPG, but doing a whole folder means clicking through export dialogs one by one. Dragging 50 files onto the page and pressing Convert once is significantly faster, and you get formats Preview can't write — like AVIF, ICO, and multi-page PDF.
🪟 Windows 10 & 11
This is where HEIC hurts the most. Windows needs the HEIF Image Extensions from the Microsoft Store just to show thumbnails, and even then Photoshop, older Office versions, and countless upload forms still reject the format. Converting to JPG or PNG sidesteps all of it without installing anything or needing admin rights — perfect for locked-down work laptops.
🤖 Android
Recent Samsung and Pixel phones can read HEIF, but older devices and many apps can't. If someone AirDropped or emailed you .heic files, open the page in Chrome, select them from Downloads, and convert right on your phone. Everything runs locally — works on mobile data without uploading a byte.
HEIC vs Every Format You Might Convert To
HEIC vs JPG
HEIC wins on technical merit; JPG wins on compatibility. That's exactly why converting is so often the answer.
HEIC vs PNG
Choose PNG when exactness matters more than size — a master copy for editing, or an image with transparent areas. For an ordinary holiday photo, it's wasteful: ~10x the bytes for detail nobody can see.
HEIC vs WebP
WebP is the practical web format. Bigger than HEIC but far smaller than JPG — and it displays in every browser your visitors are likely to use.
HEIC vs AVIF
AVIF is HEIC's closest relative — both wrap a modern video codec around a still image. In our measurements, AVIF matched a quality-90 JPG's visible quality using about 30% fewer bytes. It's royalty-free, which is why browser makers embraced it. Encoding is slower though — expect ~1 second per photo.
5 Best Practices for Converting
Keep the originals. Your HEIC files are the smallest, highest-quality version you have.
Convert once, from the original. Converting a JPG that came from a HEIC adds a third generation of loss for no reason.
Don't chase quality 100. It inflates the file substantially and adds detail your eye can't resolve. Quality 90 is plenty.
Test one photo before a big batch. Convert a single file, open it, confirm it looks right, then run the rest.
Mind your metadata. Conversion strips EXIF — that protects your GPS location, but also removes the date the photo was taken. Keep the HEIC if that matters.
How Resizo Compares to Other Converters
| Feature | Resizo | Typical Converters |
|---|---|---|
| Output formats | 10 | 2-3 |
| Server upload | Never | Always |
| Watermark | None | Often added |
| Batch size | Up to 60 photos | 1-5 free |
| Sign-up required | No | Often |
| Cost | Free forever | Freemium |
| ZIP download | Yes | Paid tier |
| PDF merge | Yes | Paid tier |
| Keyboard accessible | Yes | Rarely |
| Dark mode | Yes | Rarely |
Troubleshooting Common Issues
"No image found inside this file"
→ The file is probably the video half of a Live Photo (a .mov) rather than the picture. Copy the photo from your phone again.
A large batch stalls or the tab reloads
→ Conversion uses your device's RAM. A 48 MP photo needs a lot of it. Close other tabs and convert in groups of 10. Phones with 3 GB RAM or less should use smaller batches.
AVIF encoding is slow
→ Expected. AVIF encoding is computationally heavy and runs in software. If you need small files fast, WebP is a good compromise.
My photo came out rotated
→ Rare, but possible with unusual rotation metadata. Open the converted file in any editor and rotate it, or convert the original again after re-saving it in Photos.
The GIF looks speckled
→ GIF only allows 256 colours, so photographs get dithered. It's the best GIF can do. For clean photos, use PNG or WebP instead.
Nothing happens when I add files
→ Check that JavaScript is enabled and no content blocker is stopping the page's scripts. With scripts blocked, there's no server-side fallback.
The Technical Stack (For the Curious Devs)
The converter runs entirely client-side:
- HEIC decoding: libheif compiled to WebAssembly (LGPL v3)
- AVIF encoding: libavif via WebAssembly
-
Other formats: Native Canvas API +
toBlob()/toDataURL() - Threading: Web Workers for background processing — the UI thread never blocks
- No backend: Static site, no image-processing server whatsoever
The WebAssembly HEIC decoder loads on first use in Chrome, Edge, and Firefox. On Safari, macOS, and iOS, it's never needed because Apple devices decode HEIC natively.
Conclusion
If you use an iPhone — and at this point, who doesn't know someone who does? — you'll eventually need to convert HEIC photos. Resizo does it the right way:
- ✅ 10 output formats — not just JPG
- ✅ Up to 60 photos per batch
- ✅ Zero upload — total privacy
- ✅ No watermark, no sign-up, no daily cap
- ✅ Completely free — forever
- ✅ Works on every platform — iPhone, Mac, Windows, Android
👉 Try the HEIC → JPG Converter
My advice? Leave your iPhone on High Efficiency and enjoy the storage savings. Convert only the handful of photos that need to travel somewhere else.
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