Is it safe to upload HEIC photos to an online converter?

With most converters, your photos are uploaded to their server and processed there. Bytewitness runs the HEIC decoder in your browser using WebAssembly — your photos never leave your device. You can verify this in your browser's developer tools: no upload request is made.

Should I convert HEIC to JPG or PNG?

JPG for sharing, social media, email, and web publishing — it's universally compatible and reasonably small. PNG for maximum quality preservation and further editing — it's lossless after decode but produces much larger files (typically 4–10 MB for a 12MP iPhone photo).

HEIC to JPG: Converting iPhone Photos

Q: What is HEIC?

HEIC (High Efficiency Image Container) is the default photo format on iPhones since iOS 11. It uses HEVC (H.265) compression to store photos at roughly half the file size of an equivalent JPEG, at the same visual quality. Apple switched to HEIC to reduce storage usage on devices.

Q: Why won't my HEIC photos open on Windows?

HEIC uses HEVC compression, which requires a licensed decoder. Windows needs the HEIF Image Extensions from the Microsoft Store to open HEIC files. Without it, most Windows photo apps can't read them. Converting to JPG or PNG removes this dependency entirely.

Q: Does converting HEIC to JPG lose quality?

Minimal quality loss at high settings. The HEIC is decoded to raw pixel data, then JPEG compression is applied for the first time. At quality 90–95, the result is visually equivalent to the original for virtually all photos. The HEVC decode itself is lossless — only the JPEG encoding step introduces loss.

Last updated: June 27, 2026 · By Bytewitness

HEIC is Apple's default photo format on iPhones — smaller files, same visual quality as JPEG. But it won't open on most Windows PCs, many Android apps, and older software without a plug-in. Here's what HEIC actually is and the fastest way to convert it without uploading your photos anywhere.

What is HEIC?

HEIC stands for High Efficiency Image Container. Apple switched iPhones to this format in iOS 11 (2017) because it stores photos at roughly half the file size of a JPEG at the same visual quality. A 12-megapixel iPhone photo that would be 4–6 MB as JPEG is typically 1.5–2.5 MB as HEIC.

The compression behind HEIC is HEVC (also called H.265) — the same codec used for high-quality video streaming. It was designed for video and adapted for photos; that's why it's so much more efficient than JPEG's 30-year-old DCT algorithm.

Why it doesn't open everywhere

HEVC decoding requires a patent license. Apple pays for this on its own hardware, which is why HEIC opens natively on Macs, iPhones, and iPads. Windows, most Android devices, and most software don't have the license built in, so they can't read HEIC files without an extension. This is purely a licensing and compatibility issue — the format itself is technically excellent.

HEIC vs JPG: side-by-side comparison

Property	HEIC	JPG
File size (12MP photo)	1.5–2.5 MB typical	3–6 MB typical
Visual quality	Excellent — same as JPEG at half the size	Excellent at high settings
Compression	HEVC (H.265) — very efficient lossy	DCT — older, less efficient lossy
Transparency	Yes (alpha channel)	No
Opens on Windows	Only with HEIF extension from Microsoft Store	Universally — zero plug-ins required
Opens on Android	Depends on device and app	Universally
Social media upload	Sometimes re-converted automatically	Accepted everywhere
Editing support	Photoshop CC 2018+, Lightroom, macOS apps	Universal
Browser support	Safari only — Chrome and Firefox can't open HEIC natively	Universal

How Bytewitness converts HEIC — privately

Most HEIC converters online upload your photos to their server, process them there, and send back the result. Your photos pass through a third party's infrastructure.

Bytewitness runs the entire conversion in your browser:

A WebAssembly HEIC decoder loads in a background Web Worker thread.
Your file is decoded to raw pixel data (RGBA values) inside your browser — no network request is made.
The pixel data is drawn to a hidden HTML Canvas element.
The Canvas exports the result in your chosen format (JPG, PNG, or WebP).
You download the converted file directly — it never touched a server.

You can verify this yourself: open your browser's Developer Tools → Network tab, then convert a file. No upload request appears. The HEIC decoding is done locally using the same WebAssembly approach that professional browser-based tools use.

JPG, PNG, or WebP — which should you convert to?

Convert HEIC to JPG when:

You're sharing on social media, sending by email, or need the file to open on any Windows PC or Android device without question. JPG is universally accepted, reasonably small, and looks identical to HEIC at high quality settings. For most people, HEIC→JPG is the right choice.

Convert HEIC to PNG when:

You need the absolute best quality for further editing or print work. PNG is lossless — it stores every decoded pixel exactly. The tradeoff: a 12MP iPhone photo as PNG is typically 5–10 MB, versus 2–4 MB as JPG. Use PNG when you're doing further editing in Photoshop or another tool and don't want any additional compression.

Convert HEIC to WebP when:

You're publishing on the web and want the smallest file with modern browser support. WebP achieves sizes close to HEIC (within ~20%) while being natively supported in Chrome, Firefox, Safari 14+, and Edge. It's rarely the right choice for general compatibility, but ideal for web publishing.

Other ways to convert HEIC on iPhone or Mac

Change iPhone settings to shoot in JPG instead

Settings → Camera → Formats → Most Compatible. iPhone will capture in JPEG instead of HEIC. The tradeoff: photos are 2–3× larger and use more storage.

AirDrop to Mac (automatic conversion)

When you AirDrop a HEIC photo from iPhone to a Mac, macOS can automatically convert to JPEG for compatibility. In Finder → Preferences (Cmd+,) → General, enable "Convert HEIC to JPEG".

On Windows

Install the HEIF Image Extensions from the Microsoft Store. Once installed, the Photos app and most Windows software can open HEIC files without conversion.

Frequently asked questions

What is HEIC?

HEIC is Apple's default iPhone photo format since iOS 11. It uses HEVC (H.265) compression to store photos at roughly half the file size of JPEG at equivalent quality. You'll see .heic file extensions on photos taken with iPhone 7 or later.

Why won't my HEIC photos open on Windows?

HEVC decoding requires a license. Windows doesn't include it by default. Install the HEIF Image Extensions from the Microsoft Store to open HEIC natively, or convert to JPG for full compatibility with no plug-ins.

Does converting HEIC to JPG lose quality?

Minimal, at high quality settings. The HEIC is decoded to raw pixels (lossless), then JPEG compression is applied for the first time. At 90+ quality the result is visually indistinguishable for virtually all photos.

Is it safe to use an online HEIC converter?

Most converters upload your photos to their servers. Bytewitness runs the decoder in your browser — your photos never leave your device. You can verify this in your browser's Network tab.

Should I convert to JPG or PNG?

JPG for sharing and web use — universal compatibility, reasonable size. PNG for editing and archiving — lossless quality but 3–5× larger than JPG.

Why does Bytewitness charge credits for HEIC conversion?

HEIC decoding requires a WASM library that does genuine compute work — it's not a simple canvas re-encode like JPG→PNG. The credit cost reflects the compute reality, not an arbitrary gate. Everyday format conversions (JPG, PNG, WebP, GIF, BMP) and saving Proof Pages are always free.

Convert your HEIC photos free → Use the Bytewitness converter — 3 free HEIC decode credits, files never uploaded.