HEIC to JPG

HEIC stands for High Efficiency Image Container — it's a container format that stores photos encoded with HEVC (H.265), the same video compression standard used for 4K video, rather than the much older JPEG compression scheme from 1992. HEVC's more sophisticated compression can represent the same visual detail in roughly half the file size of an equivalent-quality JPEG, which is why Apple made it the default photo format across iPhone, iPad and Mac starting with iOS 11 and macOS High Sierra: a typical photo library takes up dramatically less local storage and syncs to iCloud faster without a visible quality difference.

HEIC also supports features JPEG never did in one file — image sequences (useful for Live Photos and burst shots), depth data for portrait-mode effects, and better handling of transparency and higher bit depths. None of that required a new file extension from the user's perspective; it just meant the photo app started producing files that look identical on-screen but are structured completely differently under the hood.

JPEG has been the universal baseline for photos on the web and in software for three decades, so essentially everything that touches an image file supports it. HEIC support, by contrast, arrived over a decade later and unevenly: recent versions of Windows 10/11 and macOS can view HEIC natively (sometimes after installing a free codec extension), but older Windows versions, most Android phones outside recent flagships, many web upload forms, and a large share of desktop software still only accept JPEG or PNG. The practical result is an iPhone photo that opens perfectly on the phone that took it, gets AirDropped or emailed, and then simply fails to open, upload, or display correctly on the recipient's end.

Converting to JPG (or PNG, if you need transparency or lossless output) sidesteps that gap entirely, since both formats are accepted essentially everywhere a HEIC file might not be — the tradeoff is the modest size increase HEIC was designed to avoid, which for a handful of photos being shared or uploaded is rarely a practical concern.

Decoding HEIC normally requires a licensed HEVC decoder, which is why early web-based converters had to upload photos to a server that had one installed. This tool instead uses a HEIC decoder compiled to WebAssembly (WASM) — code compiled to run at near-native speed inside the browser's own JavaScript engine — paired with a library that spins up a dedicated background thread (a Web Worker) so the decoding doesn't freeze the page while it runs. The upshot is that a format that historically needed server-side software to read can now be decoded, converted and handed back to you as a download without your photo ever being transmitted anywhere.