HEIC vs JPG: why iPhone photos won't upload anywhere, and how to fix it

You take a photo on an iPhone, try to attach it somewhere, and either the upload silently fails or the image shows up as a gray box with a filename ending in .heic. This isn't a bug in whatever you're using — it's a genuinely different file format that a lot of software, especially on Windows and Android, was never taught to read.

Why Apple uses HEIC at all

HEIC (High Efficiency Image Container) typically produces a file less than half the size of an equivalent JPG at the same visual quality — meaningful when a phone is taking thousands of photos with finite storage. Apple made it the default camera format starting with iOS 11. The tradeoff: HEIC is a much newer, less universally supported format than JPG, which has been a safe bet everywhere since the 1990s.

Where this actually bites

• Uploading to a web form that only checks for .jpg/.png extensions and rejects or silently drops anything else.
• Sending a photo to someone on Windows or Android who opens it and gets nothing viewable without installing a codec.
• Trying to build a PDF from photos, where most JPG-only tools simply won't accept the file.

Converting without round-tripping through email-to-yourself

The common workaround — emailing photos to yourself, which sometimes auto-converts them — is unreliable and slow. This site's HEIC to PDF tool decodes HEIC/HEIF straight to JPEG using a WebAssembly build of libheif, running entirely in your browser, then builds the PDF from the decoded images the same way JPG to PDF does. No email round-trip, and the photo never leaves your device.

One limitation worth knowing: if a HEIC file is a Live Photo or part of a burst, only the first frame converts — the motion and extra frames aren't part of a static PDF page anyway.