AVIF to PNG Converter

This tool converts AVIF images to PNG inside your browser. It is for anyone who has saved an .avif picture from a website and needs a file that an image editor, a document, an upload form or an older app will actually open — without sending the image to someone else's server.

AVIF stands for AV1 Image File Format. It is a specification from the Alliance for Open Media (AOMedia) that stores images compressed with the AV1 video codec inside a HEIF container, the same ISO base media file structure that iPhone HEIC photos use. AVIF supports lossy and lossless compression, transparency, 8-, 10- and 12-bit colour, HDR and wide colour gamuts, and animated image sequences. Sites serve it because it compresses well; the catch is that much desktop software, and many upload forms, still do not accept it.

The conversion uses your browser's own AVIF decoder — MDN lists support from Chrome 85, Edge 121, Firefox 93 and Safari 16.1. First the file's header is checked: AVIF files begin with an ftyp box whose brands say avif (a still image) or avis (an image sequence), so a JPG or WebP that was merely renamed .avif is caught and named, and a HEIC photo — same container, different codec — is identified as HEIC. Then the browser decodes the image, it is drawn onto a canvas at its full pixel size, and the canvas is saved as PNG. If your browser cannot decode the file, you get an error that says so instead of a blank image.

PNG is lossless and has a full alpha channel, so the picture is not recompressed and transparency is kept — a cut-out logo stays cut out. One caveat: browsers store canvas pixels with premultiplied alpha, so the colour of nearly transparent pixels can shift slightly; fully opaque and fully transparent areas are unaffected. The PNG is usually several times larger than the AVIF. That is the cost of lossless storage, not waste. If you need a small file that still opens everywhere, use AVIF to JPG instead.

Two limits are worth knowing. The canvas a browser draws on is 8 bits per channel in sRGB by default, so a 10- or 12-bit, HDR or wide-gamut AVIF comes out as an ordinary 8-bit sRGB PNG; how HDR brightness is mapped down is up to the browser, so the result will not look identical to the original on an HDR screen. And an animated AVIF gives you only its first frame, with a note saying so.

Everything happens on your device. The file is read into the tab's memory, converted, and offered back as a download; you can check in your browser's developer tools (Network tab) that no request carries your image. Up to 50 files per batch, each up to 50 MB.

1. Each file must be at most 50 MB. Its first bytes must be an ISO-BMFF ftyp box with an AVIF brand (avif or avis); any other format is refused with a message naming what the file really is. 2. If the ftyp brands include avis (an AV1 image sequence), you are told that only the first frame will be converted. 3. The browser decodes the file with createImageBitmap (its built-in AVIF decoder). If decoding fails, the tool stops with an error naming the browser versions that support AVIF. 4. The image is drawn onto a canvas at its original width and height — no resizing — and encoded with canvas.toBlob("image/png"), which is lossless. 5. The output keeps the original file name with a .png extension. With several files, download each or all together as a ZIP built in the browser.