What is WebP? The Modern Image Format Explained

WebP is an image format created by Google in 2010 and built on the VP8 video codec. It supports both lossy and lossless compression, transparency (alpha channel), and even animation — making it a versatile replacement for JPEG, PNG, and GIF simultaneously.

The headline benefit: a WebP image is typically 25–35% smaller than an equivalent JPEG at the same perceived quality, and 26% smaller than a lossless PNG.

WebP's lossy mode is based on predictive coding — the same technique used in modern video compression. Instead of storing every pixel independently, the encoder predicts what each block of pixels looks like based on its neighbours, then stores only the difference (the prediction error). This is far more efficient than JPEG's discrete cosine transform (DCT) approach, especially for smooth gradients and photographic content.

WebP's lossless mode uses a completely different algorithm called LZ77 with Huffman coding and a colour cache. It is specifically designed for images with sharp edges, text, or large areas of flat colour — the exact scenarios where JPEG falls apart.

WebP gives you both modes in a single format, which is unusual:

• Lossy WebP — best for photographs and images where a tiny amount of quality loss is acceptable. Produces the smallest files. Use quality 75–85 for most web use cases.
• Lossless WebP — pixel-perfect reproduction, ideal for logos, icons, screenshots, and images with text. Still beats PNG on file size.

If you're unsure, start with lossy at quality 80. The human eye rarely notices the difference on a screen.

WebP is supported by every major browser — Chrome, Firefox, Safari (since 14), Edge, and all modern mobile browsers. With 97%+ global browser coverage, there are very few reasons not to use WebP for new projects.

For the remaining 3% (primarily old iOS devices), you can use the <picture> element to serve WebP with a JPEG fallback:

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

• Product photos on e-commerce sites — smaller files load faster, directly improving conversion rates.
• Blog and article images — faster page loads improve Core Web Vitals (LCP) and SEO ranking.
• Replacing PNG icons with transparency — lossless WebP beats PNG on size while preserving exact pixels.
• Anywhere bandwidth matters — mobile users on slow connections will thank you.

• You need maximum compatibility with very old software or printers.
• Your CMS or workflow doesn't support WebP yet.
• The image is already heavily compressed — re-encoding won't help.