What Is an AVIF File? The Format That Beats WebP

Every few years a new image format arrives claiming to replace JPG, and most of them disappear. AVIF is the one that has actually stuck — not because of marketing, but because the compression is genuinely a generation ahead.

What It Is

AVIF stands for AV1 Image File Format. It takes the key frame of the AV1 video codec and wraps it as a still image. That lineage explains everything about it: AV1 was designed by a consortium including Google, Netflix, Amazon and Mozilla specifically to compress video better than anything before it, and a still image is just a video frame that never moves.

WebP did the same trick with the older VP8 codec. AVIF is the same idea, one codec generation later.

How Much Smaller

For typical photographs, AVIF lands roughly 20–30% smaller than WebP and around half the size of JPG at comparable visual quality. The gap widens at low bitrates: where a heavily compressed JPG falls apart into blocks, AVIF degrades into something softer and much less objectionable.

That low-bitrate behaviour is the practically important part. It is not that AVIF makes good images slightly smaller — it is that AVIF makes small images still look acceptable.

What It Can Do That WebP Cannot

• Wider colour and HDR. AVIF supports 10- and 12-bit colour depth and high dynamic range. WebP is limited to 8-bit. For photographs of skies, sunsets and anything with a smooth gradient, 8-bit is where banding comes from.
• Better transparency. Both support an alpha channel, but AVIF compresses it more efficiently.
• Film grain synthesis. Inherited from AV1: grain can be described and regenerated rather than stored, which is why grainy photographs compress far better than they should.

The Cost: Encoding Time

This is the trade-off nobody mentions in the comparison charts. AVIF encoding is substantially slower than JPG or WebP — not marginally, but by an order of magnitude on a complex image at high effort settings.

For a website that encodes images once and serves them a million times, that cost is irrelevant. For anything that encodes on demand — a user upload pipeline, a batch of hundreds of photos on a laptop — it is the deciding factor. This is the main reason WebP remains the pragmatic default while AVIF is the quality choice.

Support in 2026

Browser support is effectively universal now; every current browser displays AVIF. Operating system and desktop application support is further behind than WebP’s but improving steadily.

The practical consequence is the same as WebP’s, one step more acute: an AVIF downloaded from a website may not open in older desktop software, and many upload forms still reject it. Converting to JPG or PNG remains the escape hatch.

When AVIF Is the Right Choice

Use it for photographic content on a site you control, especially large hero images where the saving is measured in hundreds of kilobytes. Use it where colour fidelity matters — gradients, skies, product photography. Use it when you can encode ahead of time.

Skip it for small images, where the absolute saving is trivial and the encoding cost is not worth it. Skip it for anything you need to hand to someone else. Skip it where encoding happens in real time.

AVIF, WebP, JPG: Choosing

• Need maximum compatibility → JPG. Still opens everywhere, still good enough.
• Need a good balance → WebP. Smaller than JPG, fast to encode, broadly supported, has transparency and animation.
• Need the smallest file or the best colour → AVIF, if you can afford the encoding time.

Opening and Converting

Drag an AVIF into any modern browser and it will display. To use it elsewhere, convert it: JPG for photographs, PNG if transparency matters.

The same caution applies as with WebP — AVIF to JPG is lossy to lossy, so convert once from the best source rather than repeatedly. And if you are converting to AVIF from a JPG, remember that the JPG’s compression artefacts are now part of the image; AVIF will faithfully preserve them. Encode from the original whenever one exists.