What is an AVIF file? Open it, convert it, or keep it

What does AVIF stand for?

AV1 Image File Format. AV1 is the royalty-free video codec the Alliance for Open Media published in 2018. An AVIF stores AV1-compressed pictures in a HEIF file, the same container an iPhone’s HEIC uses. AOMedia published the AVIF specification 1.0.0 on 19 February 2019; version 1.2.0, dated 16 October 2025, is edited at Google and Apple. The makers of Chrome, Safari, Edge and Firefox all sit on AOMedia’s steering committee, and all four browsers now read the format.

The file ends in .avif, and servers label it image/avif. Its first box names the brand, avif, and that brand is how software knows the file, whatever its name says. Here is the AVIF our engine wrote from our reference photo at Auto:

Why do images save as AVIF?

Because the website sent an AVIF. Your browser tells each site which image formats it can show, in a line called the Accept header, and the site picks one. MDN calls this content negotiation: “serving different representations of a resource to the same URI”. Chrome and Edge 121 and later list image/avif first, and so does Firefox 128 and later. Safari 16.4 “fixed the accept header to correctly indicate AVIF support.”

Image services automate the choice. Cloudflare’s default setting “automatically serves the most efficient format that the requesting browser supports.” Save image as keeps what arrived, so you get an .avif. Our own pages get the same result another way: the figures on our home and converter pages sit in a picture element that lists an AVIF first and a WebP second. There the browser picks, taking the first type it can show, so Chrome saves them as .avif.

Why sites send AVIF

Sites bother because the savings are real. Our 9.8 MB camera photo at 1920 pixels wide is a 69.3 KB AVIF, against a 140.3 KB JPEG, both at Auto. Google called AVIF “one of the most commonly used image formats on the web” in 2024. The Web Almanac counted it at 1.0% of the images on mobile pages that year, almost four times its count of two years before.

How to open an AVIF file on Windows, Mac, iPhone and Android

Any current browser opens an AVIF: drag the file into a window. The photo apps need Windows’ free AV1 Video Extension, macOS Ventura, iOS 16 or Android 12 and later.

Windows 11 and 10

Install the AV1 Video Extension, free from Microsoft in the Microsoft Store. AOMedia lists what it unlocks: thumbnails and previews in File Explorer, Photos, Paint, Windows Media Player and Office. If one AVIF still fails, update the extension. Its release notes add “support for 4:4:4 and 4:2:2 video”, and 4:4:4 is what our engine writes.

Mac

macOS Ventura and later decode AVIF system-wide, so Preview and Quick Look open it. On macOS Big Sur and Monterey, Safari 16.4 or later shows it: drag the file into Safari.

iPhone and iPad

iOS 16 and later. Safari 16 shipped with iOS 16 in September 2022 with still AVIF images, and Safari 16.1 added animated ones. An iPhone on iOS 15 or older cannot show an AVIF, so convert it to JPG first.

Android

Android 12 introduced AVIF. From Android 14 the decoder and encoder are mandatory, for the format’s baseline profile. Chrome for Android shows AVIF on any recent version.

Any browser

Chrome from version 85 (August 2020), Firefox from 93 (October 2021, animation from 113), Safari 16 and 16.4, Edge from 121 (January 2024). The caniuse tables put full support at 95.35% of users.

Photoshop, GIMP and other editors

Photoshop opens, edits and saves AVIF from version 26.8, the June 2025 release; older versions need a plugin. GIMP has read and written AVIF since 2.10.22, in October 2020.

When an app refuses an AVIF: make a JPG or PNG copy

Convert the AVIF once. A JPG opens in every app and every upload form. A PNG keeps transparency and suits editing: AVIF to PNG writes one, and quality 100 keeps every pixel exactly.

Our reference photo saved as AVIF, 363.0 KB at 1920 × 1280, became a 271.6 KB JPG at Auto, 340.4 KB at quality 85, and a 972.6 KB PNG. The JPG came out smaller than the AVIF because that AVIF was saved at a high quality. The same picture saved again as AVIF at Auto weighs 123.2 KB, so the JPG copy costs 148.4 KB more than a fresh AVIF would.

• Transparency turns white in a JPG. The tool shows the fill before you save; PNG keeps the see-through parts.
• HDR comes down to 8-bit sRGB. A 10-bit HDR AVIF is tone-mapped so it looks right on an ordinary screen.
• Animated AVIFs are declined, not cut to their first frame.

On a Mac, Preview does it for one file: open the AVIF, choose File, then Export, and pick JPEG.

Is an AVIF file safe to open?

Yes. An AVIF holds picture data, not a program. The rare danger is a bug in the software that decodes it, and updates fix those. Chrome fixed two libavif flaws in version 119.0.6045.199, in November 2023 (CVE-2023-6350 and CVE-2023-6351). Microsoft fixed an AVIF parsing flaw in its AV1 decoder in August 2020 (CVE-2020-1585). Keep the browser and the AV1 Video Extension up to date; that is the whole defence.

What an AVIF file can hold: HDR, transparency, animation

More than a JPG. The specification allows 8, 10 or 12 bits a channel, HDR and wide colour, transparency, depth maps and animation, and AOMedia lists both lossy and lossless compression. One coded picture can be 65,536 × 65,536 pixels, and larger pictures are built as grids. Version 1.2.0 adds gain maps for HDR. An AVIF is a raster image, not a vector, and an image format built from a video codec, not a video.

What we write is narrower. Our engine’s AVIFs are 8-bit, full-colour 4:4:4 and lossy: Auto picks quality 50 for photos and 60 for graphics, on AVIF’s own scale. They go up to 16,384 pixels a side, and they are stills only. Transparency survives: our 512 × 512 test circle, one flat teal disc with hard edges on a transparent background, 7.9 KB as a PNG, came out as a 2.9 KB AVIF with its transparency kept, though the WebP was smaller still at 1.4 KB.

AVIF vs HEIC: the same box, a different codec

Both are HEIF files. GIMP’s release notes put it in one sentence: AVIF is “the HEIF variant using AV1 compression (instead of HEVC in the same HEIF container format”. A HEIC holds HEVC pictures, the photo format iPhones adopted with iOS 11; what that file holds is in what is an HEIC file. The gap is the licence. caniuse says HEIC is “complex and expensive to license”, and only Safari shows it, for 14.63% of users, where AVIF reaches 95.35%. A real iPhone 12 Pro HEIC of 1,956.0 KB became a 473.7 KB AVIF at Auto.

When to use an AVIF file, and when to convert it

• Use it for pictures on your own site, served with a JPEG or WebP fallback, for web-size photos and screenshots, and for HDR photos meant for HDR screens.
• Expect little from it on icons and tiny thumbnails. At 64 × 64, our AVIF weighed 0.8 KB and the WebP 1.0 KB: the container is a bigger share of a tiny file, so the gap narrows. AVIF was still the smallest at all 11 of our pixel sizes.
• Skip it for email, documents, print and upload forms that list JPG or PNG, and for editing, where a lossless PNG keeps every pixel.
• Already AVIF but too heavy? Compress AVIF keeps the format and shrinks the file.

Is AVIF better than WebP? Usually, for photos, and not everywhere: AVIF vs WebP measures both on three kinds of image. For a file someone else must open, the answer is simpler: send a JPG.