What Is WebP? The Complete Guide to Google's Modern Image Format
WebP is a modern image format developed by Google that delivers superior compression for images on the web — producing files that are 25–80% smaller than JPEG and PNG while maintaining the same visual quality. In 2025, WebP is supported by over 97% of all browsers and is the recommended format for web images by Google, Mozilla, and web performance experts worldwide.
If you've heard about WebP but aren't sure exactly what it is, why it matters, or how to start using it — this guide has everything you need. We'll cover the history of WebP, how the compression technology works, what makes it better than older formats, browser compatibility, and how to implement it on your website today.
The Origin of WebP: Why Google Created a New Image Format
To understand WebP, it helps to understand the problem it was created to solve. The two dominant image formats on the web in 2010 were JPEG and PNG — both of which were designed in the 1990s, long before smartphones, high-resolution displays, and mobile internet became the dominant way people access the web.
JPEG was standardized in 1992 as a compressed format for photographs. PNG followed in 1996 as a lossless format that supported transparency. Both formats were revolutionary at the time, but their compression algorithms were designed for the hardware constraints of the early 1990s — not for a world where billions of people access the web on mobile devices with limited bandwidth.
By 2010, Google's engineers had identified a critical insight: images were the single largest contributor to web page weight. According to the HTTP Archive, images account for approximately 50% of total bytes transferred on the average web page. Making images smaller would make the web faster for everyone.
Google's solution was WebP. The format was derived from the intra-frame encoding used in VP8, Google's open-source video codec. Google acquired On2 Technologies in 2010 (the company that developed VP8), and used the same block-based prediction techniques to create a dramatically more efficient still image format.
How WebP Compression Works
WebP achieves its impressive compression ratios through a combination of advanced techniques that simply weren't available or practical when JPEG and PNG were designed:
Predictive Coding
Instead of storing the exact color value of every pixel, WebP analyzes the relationship between pixels and stores only the differences from predicted values. The encoder looks at surrounding pixels and makes a prediction about what each pixel's color should be. Then it stores only the error — how far off the prediction was. Since neighboring pixels in most images have similar colors, the error values are small and compress extremely efficiently.
Block Transform Coding
WebP divides the image into macroblocks (typically 4×4 or 8×8 pixels) and applies a mathematical transform to each block. This converts the pixel color information into frequency components — some of which can be discarded in lossy mode because the human eye is less sensitive to them. This is similar to how JPEG works, but WebP uses more advanced transform choices that result in better quality at the same file size.
Boolean Arithmetic Coding
For the final compression step, WebP uses Boolean arithmetic coding — a more efficient entropy coding method than the Huffman coding used in JPEG. Arithmetic coding can get closer to the theoretical optimal compression for any given data distribution, which translates to smaller files with no quality loss.
Adaptive Blocking
WebP can analyze different regions of an image and apply different compression parameters to each. A smooth sky in a photograph can be compressed more aggressively than a detailed building with sharp edges. This adaptive approach means WebP finds a better compression balance across the entire image.
The result: Lossy WebP images are 25–34% smaller than JPEG images at the same visual quality. Lossless WebP images are 26% smaller than equivalent PNG files. For typical website images, file size reductions of 40–70% are common.
WebP Features: What It Supports That JPEG and PNG Cannot
Beyond raw compression efficiency, WebP offers a set of features that no single older format can match:
Lossy and Lossless Compression in One Format
JPEG only supports lossy compression. PNG only supports lossless compression. WebP supports both. You can use a single format for photographs (where lossy is preferable for the smallest size) and for graphics, logos, and UI elements (where lossless is necessary to preserve sharp edges and text). This simplifies your workflow and means your browser only needs one image decoder instead of two.
Alpha Channel Transparency
WebP supports full 8-bit alpha channel transparency, just like PNG. This makes WebP a direct replacement for transparent PNG images. The difference is size: a transparent logo saved as WebP is typically 50–70% smaller than the same image as PNG. Unlike PNG, WebP's transparency can also be combined with lossy compression — so you can have a smaller transparent image where the non-transparent pixels use lossy compression.
Animation Support
WebP supports animation like GIF, but with far better compression. A WebP animation is typically 64% smaller than the equivalent GIF at comparable quality. Unlike GIF, which is limited to 256 colors and binary transparency (pixels are either fully transparent or fully opaque), WebP animations support the full 16.7 million colors and alpha channel transparency. WebP animation is also smaller than the popular alternative of animated PNGs (APNG) in most cases.
Metadata Support
WebP supports EXIF and XMP metadata, the same metadata formats used in JPEG. This means camera settings, GPS coordinates, color profiles, and other image information can be preserved when converting photographs from JPEG to WebP.
WebP vs JPEG vs PNG vs GIF: A Full Comparison
| Feature | WebP | JPEG | PNG | GIF |
|---|---|---|---|---|
| Compression efficiency | Best | Good | Moderate | Poor |
| Lossy compression | ✓ Yes | ✓ Yes | ✗ No | ✗ No |
| Lossless compression | ✓ Yes | ✗ No | ✓ Yes | Limited |
| Transparency (alpha) | ✓ Yes (8-bit) | ✗ No | ✓ Yes (8-bit) | 1-bit only |
| Animation | ✓ Yes | ✗ No | APNG only | ✓ Yes |
| Color depth | Full color | Full color | Full color | 256 colors |
| Year introduced | 2010 | 1992 | 1996 | 1987 |
| Recommended for web | ✓ Yes | Use WebP instead | Use WebP instead | Use WebP instead |
WebP Browser Support: Is It Safe to Use in 2025?
Browser support was WebP's biggest weakness for years. When Google released WebP in 2010, only Chrome supported it. Firefox, Safari, and Edge users — a majority of the web — couldn't view WebP images at all. Recommending WebP for websites was a gamble that required providing fallback images for other browsers.
That situation changed completely between 2019 and 2021, when all major browsers added WebP support:
- Google Chrome: Supported since version 23, released October 2012
- Opera: Supported since version 12, released June 2012
- Microsoft Edge: Supported since version 18, released 2018
- Mozilla Firefox: Supported since version 65, released January 2019
- Apple Safari (macOS): Supported since version 14, released September 2020
- Safari on iOS: Supported since iOS 14, released September 2020
- Samsung Internet: Supported since version 4, released 2016
- UC Browser: Supported since 2016
As of 2025, Can I Use data shows WebP support at over 97% of all global browser usage. The remaining 2–3% of users are primarily on very old versions of iOS (pre-14) or legacy desktop Safari. For most websites, this means you can safely use WebP as your primary image format without any fallback mechanism.
If you do need to support older Safari versions, the HTML picture element provides an easy fallback: serve WebP to supporting browsers and JPEG or PNG to others, all within a single HTML tag.
Why WebP Matters for Your Website's SEO and Performance
Using WebP is not just about smaller file sizes — it has direct, measurable effects on your website's search engine rankings and user engagement.
Core Web Vitals and Google Ranking Signals
In 2021, Google officially made Core Web Vitals a ranking signal. These three metrics — Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS) — measure the user experience of loading a web page. LCP specifically measures how long it takes for the largest visible element to load, which is almost always the hero image on most pages.
Google's own tools — PageSpeed Insights, Lighthouse, and Search Console — specifically flag JPEG and PNG images and recommend switching to WebP. When Google's crawler visits your site and runs performance analysis, serving WebP images directly improves your LCP score, which directly improves your Google Search rankings.
Bounce Rate and User Engagement
Research by Google found that as page load time increases from 1 to 3 seconds, the probability of a mobile visitor bouncing increases by 32%. From 1 to 5 seconds, that probability increases by 90%. Images are often the primary cause of slow page loads. Switching to WebP reduces image payload, which reduces load time, which reduces bounce rate, which signals to Google that your content is engaging — a virtuous cycle for SEO.
PageSpeed Score Improvements
One of the most common recommendations in Google's PageSpeed Insights report is "Serve images in next-gen formats." This recommendation appears whenever the tool detects JPEG or PNG images that could be saved as WebP. Addressing this recommendation directly improves your PageSpeed score, which is both a ranking signal and a metric many website owners use to benchmark their site's health.
How to Use WebP on Your Website: 5 Practical Methods
Converting your images to WebP is straightforward. Here are the most common methods, from simplest to most advanced:
1. Simple File Replacement
Convert your existing images to WebP using a free tool like Image to WebP, replace the files in your website's image directory, and update the src attribute in your HTML from image.jpg to image.webp. This is the most direct approach and works perfectly for static websites where you control the HTML directly.
2. The HTML Picture Element (Best Practice)
The picture element lets browsers choose the best format they support automatically. The browser reads each source in order and picks the first one it can display:
<picture>
<source srcset="hero.webp" type="image/webp">
<img src="hero.jpg" alt="Hero image description">
</picture>
Browsers that support WebP will load hero.webp. Older browsers that don't will fall back to hero.jpg. The fallback img tag also serves as the alt text source for accessibility.
3. Server-Side Content Negotiation
Configure your web server (Apache or Nginx) to detect the browser's Accept: image/webp request header and automatically serve the WebP version of images. This is transparent to your HTML — your img tags can keep their original JPEG or PNG paths, and the server will deliver the right format to each browser automatically.
4. WordPress Plugins
For WordPress sites, several popular plugins handle WebP conversion and delivery automatically. ShortPixel, Imagify, EWWW Image Optimizer, and WebP Express convert your existing media library to WebP and serve the converted versions to compatible browsers without requiring any manual HTML changes.
5. Hosted Platforms (Shopify, Squarespace, Wix)
Major hosted website platforms handle WebP automatically. When you upload a JPEG or PNG image, the platform converts and serves it as WebP to browsers that support it. No configuration is required on your part.
Convert Your Images to WebP — Free, Instant, Private
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Convert Images to WebP Now →WebP Best Practices: Getting the Most from the Format
Choose the Right Quality Setting
For photographs and complex images, 75–85% quality delivers an excellent visual result with file sizes 40–60% smaller than the equivalent JPEG. For images containing text, screenshots, or sharp geometric shapes, use 85–90% to avoid visible compression artifacts. For images that must be pixel-perfect (such as logos or icons used at exact size), use lossless WebP compression.
Always Convert from Your Original Source
Convert from the highest-quality version of your image — ideally the original uncompressed file from your camera or design tool. Compressing an already-compressed JPEG to WebP will compound the quality loss from both compression steps. Start with the best quality you have and convert to WebP in one step.
Size Images for Their Display Dimensions First
Before converting to WebP, resize your image to match the dimensions at which it will be displayed. A 5000px-wide photograph converted to WebP will still be much larger than necessary if it's displayed at 800px. Resize first, then convert. This single change often reduces file size more than format conversion alone.
Use srcset for Responsive Images
For responsive websites, generate multiple sizes of your WebP image and use the srcset attribute to let the browser download only the size it needs. This prevents mobile phones from downloading desktop-sized images unnecessarily.
Common Questions About WebP
Can I edit WebP files in photo editing software?
Yes. WebP is supported in Adobe Photoshop (with the WebP plugin or versions 23.2+), GIMP (free, cross-platform), Affinity Photo, Pixelmator Pro, and most other modern image editors. macOS Preview can open and export WebP files natively.
Does converting to WebP reduce image quality?
Lossy WebP compression does reduce some image data, similar to JPEG compression. However, at 80% quality (the typical default), the difference between the original and the WebP version is virtually imperceptible under normal viewing conditions. At equivalent visual quality, WebP is simply smaller than JPEG — not lower quality.
What about AVIF? Should I use that instead?
AVIF is an even newer format that can achieve better compression than WebP in some scenarios, particularly for photographs. However, AVIF has lower browser support (~95% in 2025, slightly below WebP's ~97%), slower encoding speed, and less consistent performance across different image types. For most websites in 2025, WebP is the practical optimum. AVIF is worth watching for the future.
Conclusion: WebP Is the Right Choice for Web Images in 2025
WebP is not an experimental or niche format — it is the modern standard for web images, recommended by Google, supported by every major browser, and proven in production across millions of websites worldwide. Switching from JPEG and PNG to WebP is one of the highest-impact changes you can make to improve your website's speed, user experience, and search engine rankings.
The compression benefits are real and significant: images that are 25–80% smaller mean faster page loads, better Core Web Vitals scores, lower bounce rates, and reduced bandwidth costs. With over 97% browser support in 2025, there is no longer a meaningful reason to continue serving JPEG and PNG when WebP is smaller, supports more features, and is universally understood by modern browsers.
Converting your images to WebP is quick, easy, and free. Our browser-based tool converts PNG, JPG, GIF, BMP, TIFF, AVIF, and SVG to WebP instantly — with no upload, no registration, and no file size limits.