AVIF

AVIF (AV1 Image File Format) is a modern image format derived from the AV1 video codec developed by the Alliance for Open Media. Its main strength is very high compression efficiency — it produces files noticeably smaller than JPEG or even WebP at comparable or better visual quality. For websites this means faster loading and lower bandwidth use.

Why AVIF has the edge

AVIF inherits AV1's advanced lossy and lossless compression techniques, so it handles both photographs and graphics with sharp edges and gradients. It supports transparency (an alpha channel), a wide colour gamut and high bit-depth and HDR storage, which previously required mixing several formats. As a result a single AVIF file can replace both a JPEG and a PNG. The price for this efficiency is slower encoding and higher computational demand when generating files.

Practical application

In practice AVIF is used mainly to optimise images on web pages, which translates directly into better Core Web Vitals scores, especially the LCP metric. Because browser support is not yet fully universal, the format is usually served inside a picture element with alternatives — the browser picks AVIF if it can decode it and otherwise falls back to WebP or JPEG. The approach pairs well with lazy loading, and many modern content management systems and CDNs can generate AVIF variants automatically during image processing.

When adopting AVIF, it is worth paying attention to the file-generation process. Encoding AVIF is more computationally demanding than older formats, so with large numbers of images the optimisation step is best done ahead of time or on a capable server, with the finished variants served from a cache. The quality level matters too — overly aggressive compression can introduce visible artefacts, so it pays to test settings on a representative set of graphics before bulk-processing an entire image library.