Frequently asked questions

15 questions on HEIC conversion and privacy.

Q1. Why does iPhone save photos as HEIC?

Since iOS 11 Apple defaults to HEIC because the HEVC codec it uses halves the file size of an equivalent JPEG. You can switch back in Settings → Camera → Formats → Most Compatible.

Q2. Are my files really not uploaded?

Yes. Open the browser DevTools Network tab, start a conversion, and you will see zero upload traffic. All decoding runs inside the libheif WASM module loaded into this page. You can even go offline after the page first loads.

Q3. My HEIC does not upload to Naver blog — what do I do?

Naver blog editor rejects HEIC uploads. Drag the photo here, pick the "Naver Blog" preset (2000px JPG 85), and download the JPG — Naver accepts it directly.

Q4. What about KakaoTalk?

KakaoTalk accepts HEIC on iPhone-to-iPhone chats but Android recipients often see a broken thumbnail. Use the "KakaoTalk Share" preset (1200px JPG 80) when sharing with mixed-OS groups.

Q5. I got a HEIC from an iPhone on my Android phone — can this tool open it?

Yes. Chrome, Samsung Internet and Firefox on Android all support the WASM libheif runtime this tool uses, so you can convert HEIC files received via KakaoTalk or email without installing anything.

Q6. What happens to EXIF / GPS data?

Re-encoding through the browser canvas strips most EXIF metadata including GPS coordinates. This is a privacy-first default. If you need to preserve EXIF for archival, keep the original HEIC or use desktop tools like ExifTool.

Q7. How does a Live Photo behave here?

Live Photo consists of an HEIC still plus a paired HEVC .MOV file. This tool converts the HEIC still only. To export the motion portion separately, use the iPhone Photos app Share → Save as Video.

Q8. Why does the first conversion take longer?

The libheif WASM module (~1–3MB) is lazy-loaded on first use so the initial page load stays fast. Subsequent conversions reuse the cached module and run at full speed.

Q9. Why batches of 50?

Decoding a few hundred HEIC files at once can exhaust browser memory (libheif holds large decoded buffers). We process 50 at a time and yield to the event loop between batches so the UI stays responsive and memory stays bounded.

Q10. Is WebP safe to use in 2026?

All current Chrome, Firefox, Safari 14+, Edge and mobile browsers support WebP. Naver blog and Tistory accept WebP uploads. KakaoTalk is the only common hold-out, so use JPG for chat sharing.

Q11. Can I change the quality slider?

Each preset pins a quality value optimized for its target (85 for blog JPG, 82 for WebP, 80 for KakaoTalk). A manual slider is on the roadmap alongside per-file format override.

Q12. What about HEIC videos or bursts as a ZIP?

HEIC is for still images; HEVC video files (.MOV/.MP4) are not supported here. A future release may unzip incoming archives; for now unzip locally, then drop the folder onto this page.

Q13. How many photos can I drop at once?

Tested up to ~500 photos per session on a 16GB laptop. Beyond that memory pressure becomes noticeable; split your batch into two passes.

Q14. Does it work on mobile Safari?

Yes. iOS Safari 16+ handles the HEIC WASM pipeline natively. Due to iOS memory caps, stick to ~50 photos per batch on mobile.

Q15. Do you save or log anything?

We use privacy-friendly page analytics (GA4, Naver Analytics) for traffic counts only. No image data ever touches our servers — there are no servers to touch it.