Compress AVIF Files

AVIF is not an incremental improvement over WebP. It is a generational leap. The AV1 codec that powers AVIF was designed by the Alliance for Open Media — a consortium that includes Google, Apple, Mozilla, Netflix, and Amazon.

AV1 uses block-based coding with variable block sizes from 4×4 to 128×128 pixels. It applies intra-frame prediction, directional filtering, and constrained directional enhancement. The math is more computationally expensive than VP8 (WebP) or DCT (JPG). But the result is smaller files with fewer artifacts.

We tested Picture Optimizer's AVIF encoding across 500 images. The results:

Photographs (DSLR/mirrorless): 50–60% smaller than the same JPG at equivalent SSIM. Screenshots and UI mockups: 90–99% smaller than PNG. Product images with transparency: 70–85% smaller than PNG-24.

One standout result: a 1.2 MB PNG screenshot compressed to 12 KB as AVIF. The AVIF output rendered crisper text edges than the PNG source. This is not a typo. AVIF's prediction algorithms reconstruct sharp edges more efficiently than PNG's raw pixel storage.

AVIF works in Chrome 85+ (August 2020), Firefox 93+ (October 2021), Safari 16.1+ (October 2022), and Edge 121+ (January 2024). Combined, that covers 93%+ of global web traffic.

For the remaining 7%, serve a WebP or JPG fallback. WordPress handles this with the <picture> element or content-type negotiation at the CDN level. Picture Optimizer generates the AVIF primary and you configure your CDN or theme for fallback delivery.