About AVIF (AV1 Image File Format)
AVIF stores still images using the AV1 video codec, developed by the Alliance for Open Media — a consortium that includes Google, Netflix, Mozilla, and Apple. The format arrived in 2019 and is now displayed by every major browser. Its claim to fame is efficiency: at typical web quality settings, an AVIF file is often around half the size of an equivalent JPEG, and it also supports transparency, HDR, and 10-bit color.
Reach for AVIF when file size matters most — image-heavy websites, bandwidth-limited delivery, or shrinking a large photo collection. It is a weaker choice for archival masters, where TIFF or lossless JPEG XL make more sense, and for sending to people who may be on older software.
Convertmaxxing encodes and decodes AVIF entirely in your browser, free and without uploads. One caveat worth knowing up front: AVIF encoding is more computationally demanding than other formats, so large images can take a while to convert.
Strengths
- Best-in-class compression — often about half the size of JPEG at the same quality
- Supports transparency, HDR, and 10-bit color
- Displayed by all major modern browsers
- Royalty-free, with backing from Google, Netflix, Mozilla, and Apple
Limitations
- Encoding is slow — large images take noticeably longer than JPEG or WebP
- Older operating systems and desktop apps often cannot open it
- Lossless mode is inefficient — PNG or JPEG XL are better for lossless work
Where the extra compression comes from
A still AVIF image is, structurally, a single frame of AV1 video wrapped in a container. That sounds like a curiosity but it is the whole explanation for the format’s efficiency. Video codecs have absorbed three decades of research into predicting one part of a picture from another, and AV1 brings all of that machinery to bear on a single frame: dozens of directional intra-prediction modes, block partitioning that adapts from 128×128 down to 4×4 depending on how busy each region is, and transforms far more flexible than JPEG’s fixed 8×8 grid.
The practical result is that AVIF degrades differently from JPEG. Where JPEG falls apart into blocky squares and ringing halos, AVIF tends to smooth detail away instead — grain and fine texture quietly disappear before anything looks broken. Many people find that failure mode far less objectionable, which is part of why AVIF holds up so well at aggressive settings where a JPEG would look visibly damaged.
The cost: encoding time
All that adaptive searching has to be paid for somewhere, and it is paid at encode time. The encoder evaluates an enormous number of possible ways to describe each block and keeps the cheapest one. That is why converting a large photo to AVIF can take many seconds while the same photo becomes a JPEG almost instantly — the asymmetry is inherent to the design, not a limitation of running in a browser. Decoding, by contrast, is fast, which is the right trade for images that are encoded once and viewed many times.
This matters when you are converting in bulk. A folder of a few hundred high-resolution photos is a genuinely long job in AVIF, and because conversion here runs on your own machine, it is your CPU doing the work. If you need speed more than the last 20% of file size, WebP encodes far faster and still beats JPEG comfortably.
Frequently asked questions
- Why is converting to AVIF so much slower than other formats?
- Because the AV1 encoder searches through a very large number of ways to compress each block of the image and picks the best one. That search is what produces the small files, and it is inherently expensive. Decoding an AVIF is quick — it is only creation that is slow. Expect large images to take seconds rather than milliseconds.
- Is AVIF better than WebP?
- For file size at a given quality, generally yes — AVIF typically lands meaningfully smaller, and the gap widens at lower quality settings. WebP wins on encoding speed and on compatibility with older software. If you are optimising a website and can afford the encode time, AVIF is the stronger choice; if you need something fast and broadly supported, WebP still is.
- Why will my AVIF file not open in Photoshop or Windows Photos?
- Browser support arrived years before desktop application support did. Every major browser displays AVIF, but many image editors and older operating system versions do not recognise it without a plugin or an OS update. If you need to hand the file to someone else, convert it to JPEG or PNG first — that is one of the most common conversions people do here.
- Does AVIF support transparency?
- Yes, with a full alpha channel, and it compresses transparent images well — often much smaller than the equivalent PNG. This makes it a strong option for web graphics and logos, provided you are confident your audience is on modern browsers.