The web has moved beyond JPEG and PNG. Today, WebP and AVIF are the leading next-generation image formats, each with their own strengths. Let's dive deep into both formats to help you make the right choice.
WebP: The Established Champion
WebP was developed by Google and released in 2010. It's now supported by all major browsers and has become the de facto standard for web image optimization.
WebP Advantages
- Universal browser support (97%+ globally)
- Excellent tooling and library support
- Fast encoding - great for on-the-fly compression
- Supports both lossy and lossless compression
- Animation support (replacement for GIF)
- Alpha channel (transparency)
WebP File Sizes
Compared to JPEG at equivalent visual quality:
- Lossy WebP: 25-34% smaller
- Lossless WebP: 26% smaller than PNG
AVIF: The New Contender
AVIF (AV1 Image File Format) is based on the AV1 video codec and was released in 2019. It offers superior compression but comes with some trade-offs.
AVIF Advantages
- Best-in-class compression - smallest file sizes
- Excellent color depth - supports HDR and wide color gamut
- Outstanding low-bitrate performance - looks better at high compression
- Growing browser support (90%+ and improving)
AVIF File Sizes
Compared to JPEG at equivalent visual quality:
- 50% smaller than JPEG
- 20% smaller than WebP
Head-to-Head Comparison
| Feature | WebP | AVIF |
|---|---|---|
| Browser Support | 97%+ | 90%+ |
| Compression Ratio | Excellent | Superior |
| Encoding Speed | Fast | Slow |
| Decoding Speed | Fast | Moderate |
| Animation | Yes | Yes |
| HDR Support | No | Yes |
| Max Resolution | 16383x16383 | Unlimited |
When to Use WebP
Choose WebP when:
- Maximum compatibility is essential
- You need fast encoding (e.g., user uploads)
- Working with animated images
- Your CDN or hosting doesn't support AVIF
- Server-side encoding resources are limited
When to Use AVIF
Choose AVIF when:
- Smallest file size is the priority
- Working with high-quality photographs
- Your audience uses modern browsers
- You can pre-encode images (not on-the-fly)
- HDR or wide color gamut is needed
The Best Approach: Use Both
The optimal strategy for most websites is to serve both formats using the <picture> element:
<picture>
<source srcset="image.avif" type="image/avif">
<source srcset="image.webp" type="image/webp">
<img src="image.jpg" alt="Description">
</picture>
This approach:
- Serves AVIF to browsers that support it (best compression)
- Falls back to WebP for browsers without AVIF support
- Uses JPEG as the final fallback for older browsers
Conclusion
Both WebP and AVIF are excellent choices for modern web development. WebP offers a safe, well-supported option with great compression, while AVIF pushes the boundaries of what's possible with even better compression ratios.
For most websites in 2025, we recommend generating both formats and serving them appropriately. Tools like OctoSqueeze make this easy by automatically generating multiple formats from a single upload.
Ready to optimize? Try OctoSqueeze and generate WebP and AVIF images automatically.