What is AVIF? The image format explained

AVIF (AV1 Image File Format) is a modern, royalty-free image format that stores pictures using the compression of the AV1 video codec, and it usually makes files much smaller than JPG at the same visual quality. All current major browsers can show it, so it is a strong choice for images on a website. Below is where AVIF comes from, how it compares with WebP and JPG, where it opens, and when you are better off with something else.

What AVIF is and where it comes from

AVIF is short for AV1 Image File Format. AV1 is a video codec, the part of a video format that does the compressing, designed for streaming video over the internet. It is developed by the Alliance for Open Media, a group of companies from across the web and video industry that set out to create a high quality video format anyone can use without paying royalties. AVIF takes a single frame compressed with AV1 and wraps it in the HEIF container, the same kind of container Apple uses for HEIC photos.

The idea is simple: video codecs have improved enormously in the last decade, while JPG still uses techniques from the early 1990s. Using AV1 for still pictures brings those improvements to images. Mozilla’s documentation describes AVIF as a powerful, open source, royalty-free format, and the Alliance for Open Media describes it as an open standard.

If the name HEIF sounds familiar, it is because the iPhone uses the same container for its HEIC photos. The difference is what sits inside: a HEIC photo is compressed with HEVC, a video codec covered by patent licensing, while an AVIF image is compressed with AV1, which is royalty free. In practice that shows up in the browser: every current major browser opens AVIF, while most of them still cannot show a HEIC photo.

An AVIF file ends in .avif and its MIME type is image/avif. Beyond plain photos it supports lossless compression, transparency (an alpha channel, like PNG), animation (like a GIF but far smaller), high dynamic range (HDR) and wide color gamut, so it can hold brighter highlights and richer colors than a normal JPG.

AVIF vs WebP vs JPG

The main reason to use AVIF is size. Mozilla notes that lossy AVIF images are around 50 percent smaller than JPEG images at a similar quality, and the Alliance for Open Media claims savings of over 50 percent compared with JPEG. WebP sits between the two: Google puts lossy WebP at 25 to 34 percent smaller than JPG. A comparison cited by Mozilla found a median saving of 50 percent for AVIF against 30 percent for WebP on the same set of JPGs.

Quality holds up best where JPG struggles. At small file sizes JPG breaks into visible blocks and color bands, while AVIF tends to go soft and smooth instead, which is much less noticeable in sky, skin and gradients. On very detailed images the gap narrows, and on tiny icons the difference in kilobytes is too small to matter.

Where AVIF loses is reach and speed. JPG opens in every app and device ever made, WebP in nearly every current one, and AVIF in fewer places outside the browser. AVIF also takes longer to encode than JPG or WebP, and it does not support progressive rendering, which means a large file appears only once it is fully downloaded rather than sharpening as it loads. For a closer look at the older two formats, our guide to WebP vs JPG vs PNG goes through them in detail.

Which browsers and apps open AVIF

Every current major browser shows AVIF. According to caniuse.com, support arrived in Chrome 85, Opera 71, Firefox 93, Safari 16.4 on the Mac (with partial support from 16.1), Safari on iPhone and iPad from iOS 16, Samsung Internet 14 and Edge 121. Caniuse estimates that over 96 percent of web users worldwide are on a browser that can display AVIF.

Outside the browser the picture is patchier. Support in photo viewers, image editors, office programs, messaging apps and upload forms depends on the program and its version, and many forms and services that check file types still only list JPG and PNG. If you have received an AVIF and an app will not open it, dragging it into a browser tab is a quick way to view it.

Because of that, the usual advice, and the one Mozilla gives, is to serve AVIF on websites with a fallback in WebP, JPG or PNG for anything that cannot show it. The HTML picture element does this automatically: the browser takes the first format it understands. For photos you send to people or upload to forms, stay with JPG.

When to use AVIF

AVIF makes the most sense for images on a website, especially large ones: hero images, product photos, blog photos and backgrounds. Halving the weight of the biggest images on a page has a direct effect on how fast it loads, above all on a phone connection. It is also a good fit for images with transparency, where it can replace heavy PNGs, and for short animations that would otherwise be large GIFs.

A simple way to decide is to look at who controls the screen. On your own website you choose the format and can add a fallback, so AVIF is low risk and the speed gain is real. On someone else’s platform, such as a marketplace, a social network or a client’s content system, check what it accepts first; many convert every upload to their own format anyway, so sending an AVIF gains nothing. For a photo you are still editing, keep working in the original format and export AVIF only at the end.

It makes less sense when the file has to travel. Email attachments, documents, print orders, social media uploads and application forms are all places where JPG or PNG are expected, and an AVIF can be rejected or shown as an unknown file. It is also not worth converting small icons and thumbnails, where the saving is a few kilobytes and the extra format adds work.

How to convert an image to AVIF

Most image editors do not export AVIF yet, so a converter is the easiest route. Our PNG to AVIF converter encodes real AVIF files right in your browser, with a full AVIF encoder that is downloaded to the page only when you use it. Nothing is uploaded, and the same tool accepts JPG, WebP and iPhone HEIC photos too, not only PNG.

If you need the widest support with a solid size saving, convert to WebP instead with the PNG to WebP converter. Many sites serve both: AVIF to browsers that take it and WebP to the rest.

AVIF downsides

Encoding is slow. AVIF compresses so well partly because the encoder works hard, so saving a large photo takes noticeably longer than saving a JPG, and batch conversions in a browser can take a while on an older phone. Decoding is fine for normal use, but the format is heavier to work with than JPG.

There is no progressive loading. A progressive JPG shows a rough version first and sharpens as it downloads; an AVIF appears only once all of it has arrived. Mozilla points out that the smaller size usually makes up for this, but for very large images on slow connections it can be noticeable.

Support outside browsers is still catching up, which is the most practical downside. Many apps, upload forms and services do not accept AVIF yet. Some tools also cannot write AVIF from a canvas, which is why, on Squishly, cropping or rotating an AVIF gives you a JPG while compressing an AVIF keeps it as AVIF.

In short

AVIF is an image format based on the AV1 video codec, made by the Alliance for Open Media, open and royalty-free. It is often about half the size of a JPG at the same quality and supports transparency, animation and HDR. All current major browsers show it, so use it for images on your website with a WebP or JPG fallback, and keep JPG for photos you send or upload.