The Complete Guide to WebP Image Format: Benefits and Implementation

WebP is a modern image format developed by Google that provides superior lossless and lossy compression for images on the web. Webmasters and web developers can use it to create smaller, richer images that make the web faster.

WebP lossless images are about 26% smaller in size compared to PNGs. WebP lossy images are 25-35% smaller than comparable JPEG images at an equivalent SSIM quality index. WebP also supports lossless transparency (alpha channel) at a cost of just 22% additional bytes.

Key benefits of the WebP format

1. Superior compression

WebP’s compression algorithms reduce file sizes significantly without a visible drop in quality. Smaller payloads mean faster loading times and less bandwidth used for every visitor.

2. Transparency support

Unlike JPEG, WebP supports transparency while keeping files smaller than PNG. That makes it a good fit for logos, icons and product shots that need a transparent background.

3. Animation support

WebP handles animated images as a modern alternative to GIF, with better compression and quality. Animated WebP files are typically much smaller than their GIF equivalents.

“WebP gives webmasters and web developers a way to create smaller, better-looking images that can help make the web faster.” — Google Developers

WebP vs traditional formats

WebP vs JPEG

WebP provides 25-35% better compression than JPEG at similar visual quality, and it supports transparency, which JPEG cannot.

WebP vs PNG

For images that need transparency, WebP files are typically about 26% smaller than PNG files. WebP also supports both lossy and lossless compression, so you can choose how to balance size and quality.

WebP vs GIF

Animated WebP files are significantly smaller than GIF files and support millions of colours instead of GIF’s 256-colour limit.

How to implement WebP on your website

1. Convert your images

Start by converting your existing images to WebP. An online tool such as IMG2WEBP is the quickest route for a handful of files, while command line tools work better for large batches.

2. Use the picture element

Serve WebP with a fallback for very old browsers using the HTML picture element:

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

3. Configure your server

If you would rather not touch your markup, configure your server or CDN to negotiate the format: serve WebP to browsers that advertise support for it in the Accept header, and fall back to JPEG or PNG otherwise.

Browser support

WebP is supported by Chrome, Firefox, Edge, Safari and Opera. Safari has supported WebP since iOS 14 and macOS Big Sur, which in practice covers the vast majority of current traffic.

Best practices

• Always keep a JPEG or PNG fallback for legacy browsers.
• Compare quality at a few compression levels instead of always using the default.
• Match the quality setting to the content: photos tolerate lossy compression well, screenshots and UI text do not.
• Measure the effect on your own pages rather than assuming it worked.

Conclusion

WebP offers better compression, transparency and animation support than the formats it replaces. Converting your images takes a minute and pays off on every subsequent page view: smaller downloads, faster rendering and a smoother experience for your visitors.