Toolman

.avif — AV1 Image File Format

Image image/avif

What a .avif file is

A still-image format derived from the AV1 video codec. It compresses noticeably better than both JPEG and WebP, particularly at low bitrates, and supports HDR and transparency.

How to open it

All current browsers. Desktop image viewers are catching up; convert to PNG if something refuses it.

Worth knowing

Encoding is slow compared to WebP, which matters for user-uploaded images but not for assets you compress once.

How to identify a .avif file

A file's extension is only its name — renaming a.png to a.avif changes nothing inside. What software actually reads is the magic number, the first few bytes of the file.

Signatureftypavif at offset 4
MIME typeimage/avif
CategoryImage

Also an ISO base media container.

# what is this file really?
file mystery.avif

# look at the first bytes yourself
xxd mystery.avif | head -2
head -c 16 mystery.avif | xxd

# Windows PowerShell
Get-Content mystery.avif -AsByteStream -TotalCount 16 | Format-Hex

Converting it

You can convert AVIF in your browser without uploading it anywhere: AVIF to PNG, AVIF to JPG, AVIF to WebP.

Frequently asked questions

What is a .avif file?

A still-image format derived from the AV1 video codec. It compresses noticeably better than both JPEG and WebP, particularly at low bitrates, and supports HDR and transparency.

How do I open a .avif file?

All current browsers. Desktop image viewers are catching up; convert to PNG if something refuses it.

Is .avif safe to open?

Yes. A .avif file is data, not code — opening one cannot execute anything by itself.

Can I change a file's extension to convert it?

No. Renaming changes the label, not the bytes. The one place it appears to work is between formats that genuinely share a container — renaming .docx to .zip works because a DOCX is a ZIP. Everything else needs a real converter.

Other image formats

Other formats

All file formats