HEIC to JPG (or PNG), in your browser.

No. The HEIC decoder is WebAssembly that runs in your browser tab. Your photos never touch our servers — we don't run an image pipeline at all. You can confirm this by opening DevTools → Network, converting a file, and watching: nothing gets sent.

Only Safari can. Chrome, Firefox, and Edge never added a HEIC decoder, because the format carries patent and licensing baggage — Chrome still reports no support for it. So the tool checks first: on Safari it hands the file to the browser's own decoder and downloads nothing extra, and everywhere else it fetches an open-source one (libheif compiled to WebAssembly, about 650 KB) the first time you convert something.

Drop as many as you want. They queue up and convert one at a time, because the decoder runs in a single background worker — parallel decoding would only multiply the memory without finishing sooner. Six files including a 9-megapixel one took about a second in testing. On Safari there is no warm-up at all; elsewhere the first file waits for the decoder download and the rest are quick. When you use “Save all”, your browser may ask permission to download multiple files — allow it, or save them one at a time.

PNG is lossless — pixel-for-pixel what the HEIC held. JPG is lossy, but at the default quality of 88 the difference is not something you will see. Push the slider higher for maximum fidelity, or pick PNG if the file is going into an editor.

You get the primary still image, which for a Live Photo is the whole of what the .heic file holds — the motion lives in a separate .mov alongside it, which this tool never sees. Where a HEIC container really does hold several images, only the first is converted; we tested a two-image container and the second image was dropped. Depth maps and HDR gain maps go too. For those, a desktop app (Photos, Lightroom) is the right tool.

Yes. HEIC is the Apple-specific variant of HEIF; both decode the same way. The tool reads the file's own header rather than trusting its name, so a .heif converts fine and a JPEG someone renamed to .heic gets told what it actually is instead of being fed to the decoder.

Because HEIC is simply a better codec. The same picture costs more bytes once it is in a format every app can open — in testing a 425 KB HEIC came back as a 955 KB JPG, and the batch as a whole grew 72%. That is the price of compatibility, not a mistake. Lower the quality slider if the size matters more to you than the last of the detail.