1. What is HEIC?
HEIC (High Efficiency Image Container) is the default photo format on iPhone since iOS 11 (2017). It stores images using the HEVC/H.265 codec inside an HEIF container, producing files roughly half the size of JPEG at equal or better quality.
2. Why it is a problem outside Apple
- Naver blog, Tistory, most Korean forums, and KakaoTalk chat image uploads historically accept only JPEG/PNG. A real-world bug report: "The user tried to upload a .jpg, but the actual file type was image/heic — our platform only supports image/jpeg and image/png."
- Android phones before Android 10 cannot natively decode HEIC, so photos shared over KakaoTalk or email appear as unknown file icons.
- Windows 10 and earlier require the HEIF Image Extension, and even then preview-only mode is common.
- Most web CMSs and email clients silently reject HEIC.
3. Why convert in the browser, not on a server
Popular online converters (heictojpg.com, CloudConvert, iLoveIMG, Convertio) upload your photos to their servers. This means:
- Your photos leave your device.
- Retention policies vary, and some services keep files for hours or days.
- Batch limits (50–200 photos) and paid tiers kick in fast.
This tool decodes HEIC with the libheif WASM module (via heic2any) directly inside your browser. Nothing is uploaded — you can disconnect your network and it still works.
4. Choosing a preset
- Naver Blog (2000px JPG 85) — matches the Naver blog editor's recommended long-edge of 2000px. Great quality/size balance.
- Tistory (1600px JPG 85) — Tistory's image CDN recompresses anything bigger.
- KakaoTalk Share (1200px JPG 80) — KakaoTalk further compresses shared photos; 1200px keeps detail while staying under its ~5MB limit.
- Web Optimized (1600px WebP 82) — WebP gives 25–35% smaller files than JPG at equal quality. All modern browsers support it.
- Keep Original — no resize, near-lossless. Use when archiving or printing.
5. Live Photos and bursts
iPhone Live Photos are actually two files: the HEIC still and a paired HEVC .MOV. This tool converts only the still image. To convert the motion part, export the MOV separately from the Photos app.
6. Privacy and EXIF
Re-encoding through the canvas strips GPS and most EXIF metadata by default — a side effect that doubles as a privacy win for anyone sharing on social networks.