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AVIF: the smallest photos, the slowest to make

AVIF is an image format built on the AV1 video codec. For photographs it usually produces the smallest files of any widely supported format, handles smooth gradients well and can store HDR. The trade-offs are slow encoding and patchier support outside web browsers.

AVIF at a glance

File extensions
.avif
MIME type
image/avif
Compression
Lossy or lossless, using AV1 video compression inside a HEIF-style container.
Transparency
Yes, with smooth alpha.
Animation
Yes, as image sequences.
Colour
8, 10 or 12 bits per channel, with support for wide colour gamuts and HDR.
Browser support
All current major browsers. Edge was the last to add it, in 2024.
In ImageDoctor
Opens AVIF with the browser's own decoder, or a built-in one where the browser has none, and saves AVIF with a built-in encoder — no browser can write AVIF itself. Encoding takes seconds rather than milliseconds.

What makes AVIF small

AVIF stores a single frame of AV1 video — the codec that streaming services use for their most efficient streams. Video codecs have had decades of work put into describing natural scenes in as few bits as possible, and AV1 brings that to still images: larger, adaptive block sizes, better prediction of each area from its surroundings, and filtering that hides compression edges instead of showing a block grid.

In practice a photo that is 400 KB as a good JPEG will often be around half that as AVIF at a similar perceived quality. It is especially good at skies, skin and other smooth gradients, where JPEG tends to show banding.

The costs

  • Encoding is slow. A large photo can take seconds to encode where WebP takes milliseconds. For a handful of important images that is irrelevant; for a batch of hundreds it adds up. ImageDoctor's AVIF encoder runs in your browser, so nothing is uploaded while you wait.
  • Fine detail can soften. At aggressive settings AVIF smooths small textures rather than showing artefacts. That looks cleaner than JPEG's blockiness, but it is still lost detail — compare at 100% zoom.
  • Support outside browsers is uneven. Browsers are covered; desktop apps, operating systems and upload forms vary. A downloaded .avif may still need converting to open in an older program.
  • Small, sharp-edged graphics gain little. For icons and UI, WebP, PNG or SVG are often as small or smaller.

HDR and colour depth

AVIF can store 10- and 12-bit colour, which is enough for HDR photos and wide-gamut colour. JPEG is limited to 8 bits. Converting an HDR AVIF to JPEG therefore has to squeeze it into a smaller range, and bright highlights may look flatter or clipped. Ordinary 8-bit AVIFs — which is what most websites serve — convert without any such change.

When to use AVIF

  • Large photographs on a website — hero images, galleries, product photos — where the extra saving over WebP is worth the encoding time.
  • Photos with smooth gradients that band in JPEG.

When not to

  • Anything you send to other people or systems. JPEG is still the format everything accepts.
  • Big batches where speed matters. WebP gets most of the saving at a fraction of the encoding time.
  • Icons, logos and screenshots. Use SVG, PNG or WebP.

Convert AVIF files

Each converter runs in your browser with the output format already chosen. Add one file or a whole folder.

Common questions

Drag it into a current browser tab — Chrome, Edge, Firefox and Safari all display AVIF. If you need it in an app that doesn't support AVIF, convert it to JPG.

For photographs, AVIF is usually smaller at the same visual quality. WebP encodes much faster and is supported by more software outside the browser. Many sites use AVIF for large photos and WebP for everything else.

AVIF encoding is computationally heavy. ImageDoctor uses its own AVIF encoder running in your browser, so it works everywhere, but a large image can take several seconds.

Tools for AVIF files

Image ConverterConvert between JPG, PNG, WebP and AVIF with control over quality, transparency and background colour.Image OptimizerOne-pass web optimisation: cap dimensions, pick the best modern format and strip metadata.Image CompressorShrink JPG, PNG and WebP files by quality or to an exact target size, with a side-by-side quality check.

Keep reading

All image formats