Format
AVIF, the smallest pictures, made slowly.
AVIF compresses pictures harder than JPG or WebP. The saving is real and so is the wait.
AVIF is written by an encoder built into this page, so it works the same in every browser.
Facts
The record.
Extension
.avif.
Container and codec
A HEIF container holding a picture compressed with AV1, a video codec developed by the Alliance for Open Media and offered royalty-free.
Colour
8, 10 or 12 bits per channel, wide colour and HDR.
Transparency
Supported, with partial opacity.
Who shows it
Current Chrome, Edge, Firefox and Safari. Many upload forms, social networks and email clients do not accept it yet.
In Flex Convert
Written at Great quality, scaled for AVIF so it matches a JPG at the same number. Pictures over 48 megapixels are scaled down first.
Measured examples
What we measured.
Generated pictures converted to AVIF at this site's default quality.
| Test file | Size | Change | Time | Result |
|---|---|---|---|---|
| Detailed photo, 12 MPChrome | 2.5 MB → 1.4 MB | 44 percent smaller | 3.9 s | 31.4 dB likeness · 4000 × 3000 · Location removed |
| Smooth gradients, 12 MPChrome | 243 kB → 21 kB | 92 percent smaller | 1.2 s | 51.5 dB likeness · 4000 × 3000 · Location removed |
| App screenshot, 2400 by 1600Chrome | 162 kB → 41 kB | 75 percent smaller | 560 ms | 47.5 dB likeness · 2400 × 1600 |
Measured on November 7, 2026 in Google Chrome 157, on Apple M1 Pro. Times run from pressing Convert to the result being ready, with the page already loaded. Likeness is PSNR against the original: higher is closer, and above 40 dB the difference is hard to see. Every test file was generated for these measurements, none is anyone else's work, and each is described on the About page.
The 12-megapixel photo with fine grain went from 2.5 MB as JPG to 1.4 MB as AVIF, in 3.9 seconds. The smooth picture went from 243 kB to 21 kB, and the screenshot from 162 kB to 41 kB.
Good to know
The cost of the smallest file.
AVIF trades time for size.
Why it is slow
AV1 searches many ways to describe each block of the picture and keeps the smallest. That is where the saving comes from, and it takes far more computation than JPG. The work runs in the background, so the page stays usable while it runs.
Where AVIF wins most
Smooth skies, gradients and flat artwork shrink the most, as the table shows. A photograph full of fine grain saves less, because grain is exactly what a compressor cannot describe in few bits.
Compatibility
Current browsers show AVIF, but the world outside them is slower. Check where the picture is going. If it is refused, JPG and WebP are the fallbacks, and the original JPG still exists.
Choosing
When to pick it, and when not to.
A format is a trade. These are the trades this one makes.
Pick AVIF when
the picture goes on a web page, you control how it is shown, and a smaller download is worth a slower conversion.
Pick WebP instead when
you want a good saving with a fast conversion and wider acceptance.
Pick JPG instead when
the picture is going anywhere you cannot check.