What Is WebP Format and Why Do Websites Use It? (Full Explanation)

You have probably noticed that when you save an image from a website in Chrome, it often downloads as a .webp file instead of the familiar .jpg or .png. This shift happened gradually over the past few years as major websites — Google, YouTube, Facebook, Amazon, and thousands of others — switched to WebP as their default image format.

This article explains exactly what WebP is, how it works technically, why websites use it, and what its limitations are for everyday users.

The Origin of WebP

WebP was created by Google and first announced in September 2010. It grew out of the VP8 video codec that Google acquired when it purchased On2 Technologies earlier that year. Google realized that the techniques used to compress video frames efficiently could also be applied to still images — and that they could produce smaller files than the aging JPEG standard from 1992.

The goal was simple: create a single image format that could replace both JPEG and PNG on the web, combining lossy compression (like JPEG) with lossless compression and transparency support (like PNG) in a format that produced consistently smaller files.

Google open-sourced the format and made it royalty-free, then spent years pushing browser adoption. By 2020, all major browsers supported WebP. By 2022–2023, it had become the dominant image format served by large commercial websites.

How WebP Compression Works

WebP uses two compression modes, each technically superior to the older formats they compete with:

Lossy WebP

Lossy WebP is based on VP8 video frame encoding. It uses predictive coding — analyzing nearby pixels to predict what a pixel should look like, then storing only the difference from the prediction. This is fundamentally more efficient than JPEG's discrete cosine transform (DCT) algorithm for most photographic content.

The result: at the same quality level, a lossy WebP is typically 25–35% smaller than a JPEG.

Lossless WebP

Lossless WebP is based on a different algorithm (LZ77 + Huffman coding with a color cache) that achieves no data loss while producing files about 26% smaller than equivalent PNGs. This makes it ideal for screenshots, illustrations, diagrams, and any image where pixel-perfect accuracy matters.

WebP Features Compared to JPG and PNG

Why Websites Switched to WebP

Three main forces drove mass adoption of WebP across commercial websites:

1. Google's Core Web Vitals and Page Speed

In 2021, Google officially made Core Web Vitals — a set of metrics including page load speed — a ranking signal in search results. Faster pages rank higher. Since images are typically the heaviest assets on a webpage (often 50–80% of total page weight), switching from JPEG to WebP offers an immediate performance improvement without any other changes.

Google's own PageSpeed Insights tool explicitly flags non-WebP images with the recommendation: "Serve images in next-gen formats." This nudge alone convinced thousands of site owners to switch.

2. Bandwidth Cost Reduction

For high-traffic websites serving millions of images daily, a 30% reduction in image file size translates directly to a 30% reduction in bandwidth costs. For a large e-commerce site or image hosting platform, this can mean hundreds of thousands of dollars in annual savings.

3. Improved User Experience

Faster image loading means lower bounce rates, higher engagement, and better conversion rates on product pages. The performance improvements are especially meaningful on mobile devices and slower connections.

Browser Support for WebP

As of 2026, WebP is supported by all modern browsers:

• Chrome — Supported since version 23 (2012)
• Firefox — Supported since version 65 (2019)
• Safari — Supported since version 14 (2020, iOS 14)
• Edge — Supported since version 18 (2018)
• Opera — Supported since version 12 (2012)

Internet Explorer never supported WebP. Websites that still need to support IE (virtually none in 2026) must use a fallback system or stick to JPG/PNG.

Desktop Application Support — The Problem

While browser support is universal, desktop application support for WebP remains incomplete. This is why so many people need to convert WebP files after downloading them:

WebP vs. Newer Formats: AVIF and JPEG XL

WebP is no longer the newest image format on the web. AVIF (developed by the Alliance for Open Media) and JPEG XL are both newer and achieve even better compression than WebP — but browser support for these newer formats is still catching up.

• AVIF — 20–50% smaller than WebP in many tests. Supported in Chrome, Firefox, and Safari (2022+). Increasingly used by large platforms including Netflix and Facebook.
• JPEG XL — Excellent lossless and lossy compression, HDR support. Browser support is limited as of 2026. Chrome dropped native support in 2023, though it may return.

For the near future, WebP remains the practical standard for web images — broadly supported, well-understood, and backed by the largest search engine in the world.

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Frequently Asked Questions

Who created the WebP format?

WebP was developed by Google, originally derived from the VP8 video codec that Google acquired when it purchased On2 Technologies in 2010. Google open-sourced the format and has maintained it since, working to drive browser adoption across the industry.

Is WebP better than JPG?

WebP produces smaller file sizes than JPG at equivalent visual quality — typically 25 to 35 percent smaller. It also supports transparency (which JPG does not). However, JPG has much broader compatibility: virtually every application, device, and operating system handles JPG natively, while WebP support outside of modern web browsers is still inconsistent.

Does Windows support WebP files?

Windows 11 and recent Windows 10 installations can open WebP in the Photos app. However, many third-party applications — including older Photoshop versions, Microsoft Office (pre-365), and legacy image editors — do not support WebP. Converting to JPG or PNG is the simplest solution for cross-application compatibility.

Why did websites start using WebP?

Primarily because Google made page load speed a ranking factor in search results. Smaller image files mean faster pages, better Core Web Vitals scores, and lower bounce rates. Google's own PageSpeed Insights tool recommends serving WebP, which drove mass adoption among SEO-conscious site owners.

Can WebP images have transparent backgrounds?

Yes. Unlike JPG, WebP supports alpha channel transparency — the same feature that makes PNG useful for logos and overlays. A transparent WebP file is typically 25 percent smaller than an equivalent PNG, which is one of WebP's key technical advantages.

Can WebP images be animated?

Yes. Animated WebP is a modern alternative to animated GIF. Animated WebP files are typically 70 percent smaller than equivalent GIF animations and support full 24-bit color rather than GIF's limited 256-color palette.

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