Why Google Created WebP

By 2010, the web had a problem nobody had really solved: every image format in common use was good at exactly one thing and bad at everything else. JPEG compressed photos well but had no transparency. PNG preserved quality perfectly but bloated photo-heavy pages. GIF handled animation but at a fraction of the color depth and a much larger file size than it needed to be. Web pages were getting heavier every year, and a growing share of that weight was images — yet there was no single format built to actually fix that.

Google had a unique reason to care more than most: it ran some of the highest-traffic image-heavy products on the internet, including Search, Photos, and YouTube thumbnails, and it had just acquired a video compression company with technology nobody had thought to point at still images yet. WebP came out of asking a simple question — what if one format could do what JPEG, PNG, and GIF each did separately, only smaller?

What is WebP, and where did it come from?

WebP is an image format Google announced in September 2010, built to replace JPEG, PNG, and GIF with a single format that does what all three do, only more efficiently. Its origin is unusual for an image format: it didn't start as an image project at all.

• It started with a video codec acquisition. In February 2010, Google acquired On2 Technologies, a company whose main asset was VP8, a video compression codec. Google's engineers realized that VP8's intra-frame coding — the technique it uses to compress a single video frame — could be repurposed to compress still images.
• The lossy mode came first. WebP launched in September 2010 with lossy compression only, derived directly from VP8's prediction-based encoding, which spends bits only where a block can't be accurately predicted from its neighbors.
• Lossless and transparency came later, by design. In November 2011, Google added a separate lossless compression mode — unrelated to VP8 and built specifically to compete with PNG — along with alpha channel support, finally giving WebP feature parity with PNG.
• Animation followed. An Extended File Format added animation support, positioning WebP as a replacement for GIF as well, with full 24-bit color instead of GIF's limited palette.

The result, once all the pieces were in place, was a format that could do lossy compression better than JPEG, lossless compression better than PNG, and animation better than GIF — all inside one container.

Why Google built it instead of using existing formats

This wasn't a format built for its own sake. Google had specific, measurable reasons why the existing formats weren't good enough:

• Page speed was a Google priority, not just a developer nicety. Google has long used page speed as a search ranking signal, and images are consistently the single largest contributor to page weight. A format that meaningfully shrinks images shrinks the bulk of the average page.
• No format covered every use case. A site needing both photos and transparent graphics had to use two formats and accept that neither was optimal — JPEG for photos, PNG for everything needing transparency, with no overlap.
• Patent and licensing concerns existed around alternatives. Some proposed successors to JPEG, like JPEG 2000, never achieved broad adoption partly due to complexity and licensing friction. Google released WebP and its underlying VP8 technology under an open, royalty-free license specifically to avoid repeating that failure.
• GIF was technically outdated. GIF animations were limited to a 256-color palette from a 1987-era specification, while WebP could deliver full 24-bit color animation in a smaller file.

How WebP actually solved the problem, step by step

1. Start with VP8's intra-frame prediction. Instead of compressing each block of pixels independently like JPEG's DCT does, WebP's lossy mode predicts each block from its already-decoded neighbors and only encodes the difference — the part the prediction got wrong. Less actual data needs to be stored when the prediction is accurate.
2. Use larger, smarter blocks. WebP works with 16×16 macroblocks compared to JPEG's 8×8 blocks, meaning smooth areas of an image carry less per-pixel overhead.
3. Apply more efficient entropy coding. WebP uses a form of arithmetic coding adapted from VP8, which packs the final compressed data more tightly than JPEG's older Huffman coding approach, saving additional bits without any further quality loss.
4. Build a separate engine for lossless and transparency. Rather than bolt lossless support onto the video-derived lossy mode, Google engineer Jyrki Alakuijala designed an entirely new lossless algorithm using spatial pixel prediction, a color cache, and per-channel entropy coding — purpose-built to beat PNG rather than adapted from video.
5. Package it all in one lightweight container. WebP uses a RIFF-based container with minimal overhead, so a single file extension and a single decoder can handle lossy photos, lossless graphics, transparency, and animation — no more juggling three separate formats per project.
6. Release it openly and push adoption through Google's own products. Google shipped WebP under a free license and began supporting it in Chrome, then gradually in Photos, Gmail, and Search, using its own scale to demonstrate real-world savings and pressure other browsers to follow.
7. Wait out the slow part: browser support. Even a technically superior format is only useful once browsers decode it. WebP was effectively Chrome-only for years before Firefox, Edge, and finally Safari added native support — the last major piece falling into place in September 2020.

Common mistakes and misconceptions about WebP

1. Thinking WebP is just "Google's version of JPEG"

WebP isn't a single algorithm rebranded — it bundles a lossy mode derived from video compression, an entirely separate lossless mode built to beat PNG, transparency, and animation, all in one container. Treating it as a JPEG clone undersells what it was actually built to replace.

2. Assuming WebP was always universally supported

For roughly a decade after launch, WebP support varied significantly by browser, with Chrome leading and Safari holding out until 2020. Some older guides and tools still assume compatibility gaps that no longer exist now that support is effectively universal.

3. Confusing WebP with WebM

They're siblings, not the same thing. WebM is Google's open video container, also built on VP8; WebP is the still-image format that reuses VP8's single-frame compression technique. A WebP file contains no video data, and a WebM file isn't an image format.

4. Assuming "smaller" always means "Google compromised on quality"

The file-size reduction comes from more efficient compression techniques — better prediction, larger blocks, tighter entropy coding — not from simply turning down a quality slider further than competitors. At equivalent visual quality, WebP genuinely uses less data to represent the same image.

Real-world examples of WebP's impact

These reflect Google's published findings and broader independent measurements comparing WebP against the formats it was built to replace:

The consistent theme: WebP wasn't built to marginally improve on one format — it was built to beat each existing format at the specific job that format was known for.

WebP vs JPEG vs PNG comparison table

A side-by-side look at how WebP stacks up against the two formats it was designed to replace.

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