AVIF: smaller than WebP, slower to make, and where you can use it
4 minutes, updated 2026-11-09
AVIF is the image format built on AV1, the video codec behind much of modern streaming. For photos on a website it is the most efficient format browsers can display today, and for forms and documents it is usually the wrong choice.
How much smaller
At the same visual quality, an AVIF photo is typically 20 to 30% smaller than WebP and around half the size of a JPG. The gain is largest on photos with smooth areas such as sky and skin, and on graphics with transparency, where AVIF replaces a heavy PNG. It also keeps an alpha channel, so cut-out product shots and logos stay transparent.
Where it works
- Browsers: Chrome since 2020, Firefox since version 93, Safari since iOS 16 and macOS Ventura, Edge since early 2024.
- WordPress accepts AVIF uploads from version 6.5. Many other site builders and CDNs serve it too.
- Most government, exam and job portals do not accept it. Use JPG there.
- Older photo viewers, office suites and print services may not open it.
Why it takes longer
AV1 searches much harder for a compact way to describe each block of the picture, and no browser can write AVIF from a canvas. So the first time you choose AVIF on this site, the page fetches a 3.5 MB encoder (libavif compiled to WebAssembly) and runs it in a background worker. A 12 MP photo takes a few seconds; the page stays responsive and nothing is uploaded.
Which format to use
| Destination | Format | Why |
|---|---|---|
| Your own website, photos | AVIF, with JPG as a fallback for very old browsers | Smallest files, best page speed |
| Your own website, graphics with transparency | AVIF or WebP | Much smaller than PNG |
| Upload forms and portals | JPG | The format they are built to check |
| Email and messaging | JPG | Opens everywhere |
| Editing later | PNG | No further loss on each save |