You right-click an image on a website, save it, and get a .webp file. Your photo editor does not recognize it. The form you need to upload it to rejects it. Five years ago, this format barely existed in most people's experience. Today, it is everywhere.
WebP's rise from obscure Google experiment to the web's dominant image format is a story about performance economics, browser politics, and the slow-moving nature of software ecosystems.
Why Google created WebP
In 2010, images accounted for roughly 60% of the average web page's total size. Google, whose business depends on people browsing the web quickly, had a strong incentive to make images smaller.
WebP was built on the VP8 video codec — the same compression technology behind WebM video. Google's insight was that video compression techniques, optimized over decades, could be adapted for still images to outperform the aging JPEG standard (which dates to 1992) and the heavier PNG format.
The results were significant:
| Comparison | Size reduction |
|---|---|
| WebP vs JPEG (same quality) | 25-35% smaller |
| WebP vs PNG (same quality) | 26% smaller |
| WebP animated vs GIF | 60-80% smaller |
A format that does everything WebP is unusual because it supports lossy compression (like JPEG), lossless compression (like PNG), transparency/alpha channel (like PNG), and animation (like GIF) — all in a single format. No previous format combined all four capabilities.
The slow road to adoption
Having a better format is not enough. WebP's adoption story reveals how browser politics shape the web:
- 2010 — Google releases WebP. Only Chrome supports it.
- 2011-2014 — Opera adds support. Firefox and Safari refuse, citing concerns about format fragmentation.
- 2018 — Firefox 65 finally adds WebP support after years of resistance.
- 2020 — Apple adds WebP support to Safari 14 and iOS 14 — the last major holdout.
- 2022-present — With universal browser support, adoption accelerates rapidly.
The 10-year gap between creation and universal support explains a lot. Website developers could not safely use WebP until every major browser supported it, because serving an unsupported format means broken images. The <picture> HTML element, which allows serving different formats to different browsers, was the bridge technology that enabled gradual adoption.
Why every website uses it now
The incentives for websites to serve WebP are overwhelming:
- Google's search algorithm factors page speed into rankings. Google PageSpeed Insights explicitly recommends WebP. Not using it lowers your performance score.
- Bandwidth costs money. A large e-commerce site serving millions of images saves thousands of euros monthly by switching from JPEG to WebP.
- User experience improves. A page with 20 product images saves 2-3 MB with WebP. On mobile connections, that is the difference between a 2-second and a 6-second page load.
- CMS platforms automate it. WordPress converts images to WebP automatically since version 5.8. Shopify, Squarespace, and most modern platforms do the same.
The result is that when you save an image from the web today, you almost always get WebP — even if the original was uploaded as JPEG. The server detects that your browser supports WebP and serves the optimized version.
The compatibility problem outside browsers
WebP works perfectly in web browsers, which is what it was designed for. The problem is that images do not stay in browsers:
- Office software — older versions of Word, PowerPoint, and Excel do not support WebP
- Image editors — pre-2021 versions of many editors cannot open WebP files
- Print services — online printing services typically require JPEG, PNG, or TIFF
- Government and institutional forms — almost universally require JPEG or PNG
- Email clients — WebP in email body renders inconsistently across clients
This creates a frustrating gap: the web serves WebP, but many downstream uses require JPEG or PNG. The practical need for format conversion is not going away anytime soon.
| Context | WebP supported? |
|---|---|
| Web browsers (all modern) | Yes |
| Windows 11 / macOS Ventura+ image viewers | Yes |
| Microsoft Office (recent versions) | Yes |
| Older software, print services, forms | Generally no |
AVIF: the next generation
WebP is not the end of the story. AVIF (AV1 Image File Format), developed by the Alliance for Open Media (Google, Apple, Mozilla, Microsoft), promises even better results:
- 20% smaller than WebP at equivalent quality
- Superior handling of fine details and gradients
- Better HDR and wide color gamut support
- Based on the modern AV1 video codec
AVIF browser support is growing (Chrome, Firefox, and Safari all support it now), but adoption is following the same slow pattern as WebP. It will likely take several more years before AVIF replaces WebP as the web default, and when it does, it will create the same compatibility headaches WebP causes today.
The cycle repeats: better compression, slow browser adoption, eventual ubiquity, and a long tail of compatibility issues outside the browser.
Going further
When you need to convert WebP images for use outside the browser:
- Convert WebP to JPG — instant conversion, processed locally in your browser
- Image Converter — convert between all major image formats
Both tools are free and process your files entirely on your device.