What is HEIC and why do iPhones use it?
HEIC (High Efficiency Image Container) is the format Apple uses by default on iPhones since iOS 11. It stores photos at roughly half the file size of a JPEG while keeping the same visual quality — useful when your phone holds thousands of photos. The format is based on the HEIF standard and supports features like 16-bit colour depth and live photo data that JPEG cannot carry. Apple made HEIC the default camera format across every iPhone from iOS 11 (2017) onwards — meaning virtually all photos taken on a modern iPhone are stored as HEIC. With over a billion active iPhones worldwide, HEIC is one of the most-produced image formats on the planet despite its near-zero presence in web publishing or desktop software.
The problem is compatibility. Windows, many Android apps, older editing software, and most web upload forms still expect JPEG. When you AirDrop a photo to a non-Apple device or attach it to an email on a Windows PC, HEIC often shows up as an unrecognised file. Converting HEIC to JPG makes the photo universally usable without changing how it looks.
Why convert HEIC to JPG without uploading?
Most online converters work by uploading your photo to a server, processing it there, and sending the JPG back. That means your personal photos — often containing GPS coordinates, faces, and timestamps embedded in EXIF metadata — pass through a third party's infrastructure.
LocalJPG converts entirely inside your browser using WebAssembly. The HEIC file is decoded on your device by a compiled version of libheif, then re-encoded as JPEG using MozJPEG at quality 85. Nothing is transmitted. You can verify this by opening DevTools → Network before dropping a file: the request log stays empty.
Does converting HEIC to JPG lose quality?
Yes — JPEG is lossy, so every conversion involves some quality trade-off. In practice, at quality 85 the difference is imperceptible for photos intended for sharing, email, or web use. If you need to preserve maximum fidelity (for printing or archiving), consider keeping the original HEIC alongside the converted JPG.
EXIF metadata — camera model, exposure settings, GPS location, orientation — is preserved during conversion. The raw APP1 block is extracted directly from the HEIC container and injected into the JPEG file, so photo library software and editing tools will read the metadata correctly.
Batch converting HEIC photos from iPhone
Drop an entire folder of HEIC files onto the converter at once — it processes them in parallel using a Web Worker so your browser stays responsive. Each file converts independently, so a single large photo won't block the rest of the queue.
Download each converted JPG individually, or grab all files at once as a ZIP archive — both free. The ZIP is assembled in-browser using streaming compression — it never touches a server.
Also available: WebP to JPG, PNG to JPG, AVIF to JPG
Related: iPhone photos not opening on Windows · Convert HEIC without uploading