What Is an AVIF File? The New Image Format Explained

An AVIF file is a next-generation image saved in the AV1 Image File Format, a modern, royalty-free format that produces pictures roughly half the size of a JPEG at the same visual quality. If you have run into a .avif file and could not open it, or noticed that images you saved from a website arrived with an unfamiliar extension, you have met the most efficient mainstream image format available today.

AVIF matters because it represents the biggest jump in image compression in more than a decade. The format squeezes photographs down dramatically while adding capabilities older formats never had: high dynamic range, wide color, transparency, and even animation. The trade-off is the one every new format faces at first, which is compatibility. Every current web browser displays AVIF without any help, but plenty of desktop programs, email clients, upload forms, and print services still do not accept it.

This guide explains what an AVIF file actually is, how it achieves such small sizes, how it compares to JPEG and WebP, where it works today, and exactly what to do when something refuses to open one.

Where AVIF Came From

AVIF stands for AV1 Image File Format. The name points directly at its origin: the format is built on the intra-frame compression tools of AV1, a modern video codec. In other words, AVIF takes the technology that compresses a single frame of high-efficiency video and applies it to still pictures.

AV1 itself was developed by the Alliance for Open Media, a consortium whose members include Google, Apple, Microsoft, Amazon, Netflix, and Mozilla. The still-image specification was published in early 2019. That backing matters for a practical reason: because so many of the companies that build browsers, operating systems, and streaming platforms sit inside the same alliance, support arrived across the industry unusually quickly for a brand-new format.

There is one more structural detail worth knowing. AVIF stores its image data inside the HEIF container, the same wrapper Apple uses for the HEIC photos your iPhone creates. The container is shared, but the compression inside is different: HEIC uses HEVC, while AVIF uses AV1. That distinction has consequences we will come back to.

Why AVIF Files Are So Much Smaller

The efficiency gains are the whole point of the format, and they are substantial. At equivalent visual quality, an AVIF image is typically around 50 percent smaller than the same picture saved as a JPEG. Compared with WebP, which was itself a major improvement over JPEG, AVIF still comes out roughly 30 to 50 percent smaller.

Those numbers come from genuine technical advances rather than marketing. JPEG relies on compression techniques designed in the early 1990s: it divides an image into eight-by-eight pixel blocks, transforms them into frequency information, rounds off the details the eye is least likely to miss, and packs the result using a relatively simple encoding scheme. AVIF follows the same broad strategy but executes every stage with far more sophistication. Its prediction and transform tools are more flexible, its quantization can adapt block by block rather than applying one blunt setting across the picture, and its final encoding step uses an adaptive arithmetic coder that models the specific content of the image instead of relying on a fixed table.

The practical result is that AVIF makes smarter decisions about what to keep. Where a heavily compressed JPEG produces the blocky squares and haloed edges everyone recognizes, AVIF at a comparable file size holds together far better, keeping edges cleaner and gradients smoother.

AVIF also offers a lossless mode that preserves every pixel exactly. For photographic content, lossless AVIF files usually run 20 to 30 percent smaller than the equivalent PNG. Worth noting, though, is that PNG can still be more efficient for very simple graphics built from flat blocks of color, so lossless AVIF is not automatically the winner in every case.

What AVIF Can Do That JPEG Cannot

Smaller files are only part of the story. AVIF is a genuinely more capable format, and several of its features close long-standing gaps in JPEG.

Transparency. AVIF supports an alpha channel, so images can have transparent backgrounds. JPEG never could, which is why logos and icons have always had to be PNGs. AVIF handles both photographic content and transparency in one format.

High dynamic range and wide color. AVIF supports color depths up to 12 bits, compared with JPEG's 8 bits, along with wide color gamuts and HDR metadata. In practice, that means smoother gradients in skies and shadows, and the ability to represent the brighter, more saturated colors that modern displays can actually show. Where a JPEG might produce visible banding across a sunset, AVIF has enough color information to render it cleanly.

Animation. AVIF can store animated sequences, positioning it as a replacement for the ancient GIF format at a fraction of the file size and with vastly better color.

Both lossy and lossless modes. One format covers the photographic use case that JPEG served and the pixel-perfect use case that PNG served, which simplifies things considerably for anyone building a website.

AVIF Compared With JPEG, PNG, and WebP

Placing AVIF alongside the formats it aims to replace makes the picture clearer.

Against JPEG, AVIF wins decisively on size and capability. JPEG's only remaining advantage is universal compatibility, which is not a small thing, but it is JPEG's sole edge. Every device and program on earth reads a JPEG, which is exactly why converting to JPEG is still the standard fix when compatibility matters more than efficiency.

Against PNG, AVIF wins on photographic content and matches PNG's transparency and lossless capability. PNG holds its ground for simple graphics with flat colors and for the guarantee that any software will open it.

Against WebP, the comparison is closer and more interesting, since WebP is also a modern format that combines small photographic files, transparency, and animation. AVIF generally compresses better, especially at lower file sizes and with HDR content. WebP, however, has been around since 2010, is supported by a wider range of software beyond browsers, and encodes considerably faster. AVIF encoding is computationally heavy, which can matter if you are processing thousands of images.

There is also a licensing distinction that shapes adoption behind the scenes. AVIF is built on AV1, which is royalty-free and free for anyone to implement. HEIC, by contrast, depends on HEVC, which carries patent licensing requirements. That difference is a major reason AVIF spread across browsers quickly while HEIC largely stayed within Apple's ecosystem.

Where AVIF Works, and Where It Does Not

Support splits cleanly along one line: browsers support AVIF, and a lot of other software still does not.

On the browser side, coverage is now broad. Chrome, Firefox, Safari, and Edge all render AVIF natively, which means the vast majority of people visiting a website will see AVIF images without any issue at all. This is why web developers have adopted the format so enthusiastically.

Operating systems have been catching up. Recent versions of Windows and macOS can display AVIF in their built-in image viewers, sometimes after installing an extension, and modern Android and iOS versions handle it as well. Support here is newer and patchier than in browsers, so older machines are likely to struggle.

The friction shows up in everything else. Many desktop editing programs, email clients, social media upload forms, print services, document tools, and content management systems still do not accept AVIF files. This is the source of nearly every complaint about the format: an AVIF file that looks perfect in a browser is rejected the moment you try to attach it, upload it, or open it in an older application.

The simplest way to view an AVIF file, incidentally, is to drag it into a web browser window. Because AVIF is fundamentally a web format with universal browser support, this works every time and requires nothing to be installed.

How to Convert an AVIF File for Full Compatibility

When a program or website refuses an AVIF file, converting it to an older format solves the problem in seconds, and the right destination depends on what the image contains.

For most situations, JPEG is the target. It is accepted essentially everywhere, which makes it the reliable choice for emailing an image, uploading to a form that rejects modern formats, or opening a picture in older software. A browser-based image converter handles this without any installation: upload the file, choose your output format, and download a version that works anywhere.

If your AVIF image has a transparent background, such as a logo or icon, converting to JPEG would fill that transparency with a solid color, so PNG is the better destination in that case. Working the other way, if you have PNG files that are photographic and unnecessarily large, you can convert PNG to JPG to shrink them dramatically, since JPEG's compression is built for photographs while PNG's is not.

There is also a pragmatic middle path worth considering. If AVIF's compatibility gaps are causing you trouble but you still want files much smaller than JPEG, WebP is the sensible compromise: it is far more efficient than JPEG while enjoying broader software support than AVIF. You can convert JPG to WebP to modernize a photo library for the web, and if you receive WebP files that some older program will not accept, you can convert WebP to JPG to fall back to universal compatibility. Many teams settle on WebP precisely because it captures most of the size savings with fewer headaches.

One caveat applies to any conversion away from AVIF. Because JPEG and PNG are less efficient formats, the converted file will usually be noticeably larger than the AVIF you started with, sometimes several times larger. If that pushes you past an upload limit or slows down a web page, run the result through an image compressor to bring the size back under control. A modest amount of compression on the converted file typically reclaims most of the difference with no visible change.

Should You Use AVIF on Your Own Website?

If you run a site, AVIF is worth serious consideration, because page speed affects both user experience and search visibility, and images are usually the heaviest thing on a page. Cutting image weight in half is a meaningful performance win.

The standard professional approach is not to choose one format but to serve several in order of preference, letting each visitor's browser take the best one it understands. Using a <picture> element, you can offer AVIF first, WebP as a fallback, and JPEG as a final safety net. Modern browsers take the AVIF and load fast; anything older quietly falls back without the visitor noticing. This gives you AVIF's savings with none of its compatibility risk.

Two practical considerations temper the enthusiasm. AVIF encoding is slow compared with JPEG or WebP, so building AVIF versions of a very large image library takes real processing time. And your content management system or build pipeline needs to support generating and serving the format, which not every platform does smoothly yet. For many sites, standardizing on WebP delivers most of the benefit with far less friction, and adding AVIF for the largest, most important images gives you the best of both.

Final Thoughts

An AVIF file is a modern, royalty-free image built on AV1 compression that delivers roughly half the size of a JPEG at the same quality, while supporting transparency, HDR, wide color, and animation that older formats cannot match. Every major browser displays it, which is why so much of the web has adopted it, but plenty of desktop software, email clients, and upload forms still do not.

The workflow that follows from this is simple. Drag an AVIF into a browser to view it. Convert it to JPEG when something demands broad compatibility, or to PNG when you need to keep transparency. Compress the converted file if it comes out larger than you want. And if you are publishing images yourself, serve AVIF with WebP and JPEG fallbacks so fast browsers get the small file and older ones still see your pictures. Understood that way, AVIF stops being a puzzling extension and becomes what it was designed to be: the most efficient way yet to put a high-quality image on a screen.