WebP vs AVIF: Which Image Format Should You Use?

WebP and AVIF are the two modern image formats worth caring about in 2026. Both can produce dramatically smaller files than JPG or PNG without visible quality loss, but they're not interchangeable, and "AVIF is newer so AVIF is better" isn't a useful answer.

This post compares them on the things that actually matter: file size, browser support, encoding speed, and the quirks you'll hit if you swap one for the other.

File size, in real numbers

For a typical 4000×3000 photo from a phone camera, here's what we usually see:

• JPG (quality 85): ~1.8 MB
• WebP (quality 80): ~900 KB, roughly 50% smaller than JPG
• AVIF (quality 60): ~450 KB, another 40–50% smaller than WebP

The exact numbers depend on the photo's content (skies and skin tones compress better than dense foliage or text), but the ranking is consistent: AVIF wins on size, WebP is a close second, and both crush JPG.

For graphics with flat color and sharp edges (UI screenshots, charts, logos), the size advantage of AVIF over PNG is even larger because AVIF supports both lossy and lossless modes well.

Browser support

Both formats are now supported by every modern browser. WebP has been universal since Safari 14 (2020), AVIF since Safari 16.4 (2023). If your audience uses anything from the last three years, both formats render natively without a fallback.

The only real holdouts in 2026 are some embedded WebViews on legacy Android and very old corporate Windows installs. If those are part of your audience, serve a JPG fallback via <picture>:

<picture>
  <source srcset="hero.avif" type="image/avif">
  <source srcset="hero.webp" type="image/webp">
  <img src="hero.jpg" alt="Hero image">
</picture>

Encoding speed

This is where the formats differ in a way that matters operationally:

• WebP encodes fast. A 4000×3000 image takes well under a second in a browser using WASM.
• AVIF is significantly slower. The same image can take 5–15 seconds in a browser, depending on the encoder settings and CPU.

If you're batch-converting hundreds of files in a build pipeline, this difference adds up. WebP is friendly to "encode every image, every build." AVIF rewards being more selective: encode it once, cache the output, ship it.

When to use WebP

• Default for almost any web image where you care about file size.
• Bulk processing where encode time matters.
• Anywhere you'd previously have used PNG with transparency. WebP supports lossy and lossless transparency, often at half the PNG size.
• When older browsers are still in your audience but you don't want to ship JPG.

When to use AVIF

• Hero images and "above the fold" assets where the extra 40% size cut directly improves Largest Contentful Paint.
• Very large images (4K+) where WebP's compression starts to flatten and AVIF still has headroom.
• Photo-heavy galleries that are encoded once and served many times: the slow encode is amortized.
• Anywhere the savings matter more than the encode time.

When to use neither

• Logos and icons: use SVG. It's vector, infinite resolution, and tiny.
• Animated content: both AVIF and WebP support animation, but if you're already shipping a video player, AV1 or HEVC video at the same bitrate looks dramatically better than animated stills.
• Print or archival: both are lossy by default. Keep a non-destructive original.

A practical rule

If you're picking one format and shipping every image in it, ship WebP. It's the best balance of size, encode speed, support, and predictability for a 2026 web app.

If you can afford a tiny extra step in your build pipeline, ship both: AVIF first via <picture>, WebP as the fallback. You get AVIF's size savings on supporting browsers and WebP's ubiquity for the rest.

If you're converting one-off images by hand, just use WebP. The marginal AVIF savings on a single image rarely justify the slower encode.

You can convert PNGs to WebP, or images to AVIF, in your browser with OmegaPix: files never leave your device, and the WASM encoders are the same ones browsers themselves ship.