WebP Images: The Complete Guide for Web Developers

WebP is an image format developed by Google and released in 2010. It was designed from the ground up to replace both JPEG (for photographs) and PNG (for graphics with transparency) with a single format that achieves better compression than either. As of 2024, WebP has over 96% browser support globally and is the recommended format for most web images. Yet many developers and website owners are still serving JPEG and PNG files, missing significant performance gains.

What is WebP?

WebP is a raster image format based on the VP8 video codec, the same technology that powers Google's WebM video format. It supports both lossy compression (like JPEG) and lossless compression (like PNG), as well as transparency (like PNG) and animation (like GIF). This versatility makes it a genuine replacement for all three legacy formats.

The key technical achievement of WebP is its use of predictive coding: each block of pixels is predicted from neighbouring blocks, and only the difference (residual) is stored. This is more efficient than JPEG's Discrete Cosine Transform approach, particularly for smooth gradients and large uniform areas.

WebP vs JPEG vs PNG: File Size Comparison

*Google internal benchmarks. Results vary by image content.

Browser Support in 2024

WebP is now supported in all major modern browsers:

• Chrome/Chromium: Supported since version 23 (2012)
• Firefox: Supported since version 65 (2019)
• Safari: Supported since Safari 14 / iOS 14 (2020)
• Edge: Supported since version 18 (Chromium-based)
• Opera: Supported since version 12

The main remaining gap is Internet Explorer (no WebP support) and certain email clients. If your analytics show significant IE traffic or your images will be used in email, provide JPEG/PNG fallbacks.

When to Use WebP

Use WebP in these situations:

• Website photographs: Any photo on a webpage — hero images, blog thumbnails, product images — should be WebP. The lossy WebP at quality 80 is typically indistinguishable from JPEG quality 85 at 25–35% smaller file size.
• Replacing PNG graphics for the web: If a PNG is used on your website (logo, icon set, illustration), convert it to lossless WebP for an immediate size reduction.
• Replacing animated GIFs: Animated WebP files are dramatically smaller than GIFs — Google reports 64% smaller — with better colour depth (GIF is limited to 256 colours).
• E-commerce product images: High volumes of product images in WebP significantly improve Core Web Vitals scores and reduce bandwidth costs.

Do not use WebP for:

• Email attachments or inline images (email clients lack WebP support)
• Images that will be printed (JPEG or TIFF remain better for print workflows)
• Images downloaded and shared by users (JPEG/PNG are more universally openable)
• Very small images under 1 KB (format overhead may increase file size)

How to Convert to WebP

Using CompressImg.in: Our WebP compressor converts JPEG and PNG files to optimised WebP directly in your browser. No software to install, and your images are never uploaded to a server — all processing happens locally.

Using cwebp command-line tool: Google provides cwebp as a free command-line tool:

cwebp -q 80 input.jpg -o output.webp

The -q flag controls quality (0–100). Quality 75–85 is the standard range for lossy WebP — visually equivalent to JPEG quality 85–90 at significantly smaller file sizes.

In Next.js: Next.js automatically converts images to WebP when using the<Image> component from next/image. No manual conversion needed — the framework serves WebP to supporting browsers and falls back to JPEG for others.

In WordPress: Plugins like ShortPixel, Smush, or EWWW Image Optimizer automatically convert uploaded images to WebP and serve them using the picture element or WebP redirection via .htaccess.

WebP Quality Settings Explained

WebP lossy quality works similarly to JPEG quality but with different characteristics:

WebP Limitations

Despite its advantages, WebP has some genuine limitations:

• Encoding speed: WebP encoding (especially lossless mode) is slower than JPEG encoding. For applications that generate images on the fly (e.g., user-uploaded avatars), this can add latency unless WebP conversion is done asynchronously.
• Limited tool support: Some older image editors do not natively open WebP. Adobe Photoshop required a plugin until version 23.2 (2022). Most modern tools now include WebP support.
• Email client support: As covered in our email guide, WebP is not suitable for email.
• AVIF is the future: AVIF (based on the AV1 codec) achieves 20–50% better compression than WebP. As AVIF browser support matures (currently ~80% globally), it will likely replace WebP as the recommended format over the next few years.

Conclusion

WebP is the best available production-ready image format for websites today. With over 96% browser support, it offers meaningful file size reductions over JPEG and PNG with no perceptible quality loss at standard settings. If your website is still serving JPEG and PNG images without a WebP conversion strategy, implementing one is one of the highest-return performance improvements available to you right now.