What Is WebP? Google's Modern Image Format Explained

WebP is the image format Google built to make the web faster. It produces smaller files than JPEG, supports transparency like PNG, and handles animation like GIF — all in a single format. Since every major browser now supports it, WebP has become the default recommendation for web images in 2026.

Here's what the format actually does under the hood, how it compares to the alternatives, and when you should (and shouldn't) use it.

WebP at a Glance

How WebP Compression Works

WebP borrows its compression technology from video codecs. If you understand how video compression squeezes hours of footage into manageable file sizes, WebP's approach will feel familiar — it applies the same techniques to individual still images.

Lossy WebP (VP8)

Lossy WebP uses Google's VP8 video codec, treating each image as a single video frame. The encoder:

1. Divides the image into macroblocks — 16×16 pixel regions, each processed independently.
2. Predicts pixel values from neighboring blocks using spatial prediction (intra-prediction). The encoder picks from four prediction modes for luma and the best matching mode for chroma. If a prediction is close to the actual pixels, only the small difference needs to be stored.
3. Applies a discrete cosine transform (DCT) to the prediction residuals, converting spatial data into frequency coefficients. High-frequency coefficients (fine detail) get quantized more aggressively — this is where the controlled quality loss happens.
4. Entropy-encodes the result using boolean arithmetic coding, which is more efficient than JPEG's Huffman coding.

The combination of better prediction, finer quantization control, and arithmetic coding is why lossy WebP files are 25-34% smaller than equivalent-quality JPEGs, according to Google's published comparisons.

Lossless WebP (VP8L)

Lossless WebP uses a completely different algorithm from lossy mode. VP8L applies a series of reversible transforms before the final compression:

1. Subtract green transform — stores red and blue channels as differences from the green channel. Since natural images have high correlation between RGB channels, this reduces entropy significantly.
2. Predictor transform — for each pixel, VP8L selects from 13 spatial predictors and stores only the prediction error.
3. Cross-color transform — decorrelates the color channels further by encoding inter-channel relationships.
4. Color indexing transform — if the image uses few colors (≤256), VP8L automatically switches to a palette-based mode.
5. LZ77 backward references — finds repeating pixel patterns and replaces them with references to earlier occurrences.
6. Huffman coding — entropy-encodes the final stream.

The result: lossless WebP files are 26% smaller than equivalent PNG files on average. The advantage is most pronounced on photographic content, where the spatial prediction transforms have more redundancy to exploit.

Lossy vs Lossless WebP

WebP's dual-mode design means you pick the compression type based on your content:

Lossy WebP works best for photographs and complex images with smooth gradients, many colors, and no hard edges that need pixel-perfect preservation. Quality is controlled by a 0-100 parameter — quality 75-80 is the sweet spot for web images, producing files that are visually indistinguishable from the original at typical viewing sizes.

Lossless WebP works best for graphics, screenshots, illustrations, logos, and any image where every pixel matters. No quality parameter — the output is bit-for-bit identical to the input. File sizes are larger than lossy but still smaller than PNG.

A unique WebP feature: lossy compression with alpha channel. JPEG forces you to choose between small files (lossy, no transparency) and transparency (PNG, large files). WebP lets you have both — a lossy-compressed image body with a separately compressed lossless alpha channel. This is particularly useful for product photos on transparent backgrounds.

For a deeper dive into the tradeoffs between lossy and lossless compression across all formats, see Lossy vs Lossless Image Compression.

WebP vs Other Formats

Key takeaways from the comparison:

• WebP vs JPEG: WebP wins on file size (25-34% smaller), adds transparency and animation, and is supported everywhere JPEG is supported in modern browsers. The only reason to choose JPEG over WebP is backward compatibility with very old software.
• WebP vs PNG: Lossless WebP is 26% smaller than PNG with identical quality. WebP also adds animation support. PNG's advantage is broader software support outside browsers (print tools, legacy editors) and 16-bit color depth. See the full comparison at PNG vs WebP.
• WebP vs AVIF: AVIF compresses roughly 20% better than WebP and supports 10/12-bit HDR. But AVIF encoding is dramatically slower (sometimes 100× slower), and browser support is narrower — Safari only added AVIF in version 16.4 (2023). For a detailed breakdown, see WebP vs AVIF.
• WebP vs GIF: Animated WebP files are significantly smaller than equivalent GIFs with better color reproduction (24-bit vs 8-bit). For more on GIF's history and limitations, see What Is GIF?.

For help choosing the right format across all use cases, see Best Image Format for Web.

Browser Support

WebP support was a pain point for years. Google shipped support in Chrome 17 (2012), but Safari held out until version 14 (2020). That gap forced developers into fallback gymnastics with <picture> elements and multiple source files.

That era is over. As of 2026, every major browser supports WebP:

Safari 14+ means every iPhone running iOS 14 or later displays WebP natively. Since Apple drops iOS support aggressively (iOS 14 requires iPhone 6s or later, released in 2015), the percentage of active iPhones that cannot display WebP is negligible.

Global browser support for WebP exceeds 97% of web users according to Can I Use. The remaining ~3% is almost entirely legacy browsers on unmaintained systems. Unless your analytics show meaningful traffic from Internet Explorer or pre-2019 browsers, you can serve WebP without fallbacks.

When to Use WebP

WebP is the right choice when you need:

Smaller photo files for web pages. Replace JPEG with lossy WebP at quality 75-80. Expect 25-34% file size reduction with no visible quality difference. This directly improves page load times and Core Web Vitals scores — particularly Largest Contentful Paint (LCP), which Google uses as a ranking signal.

Transparency without the PNG tax. Product photos, logos, and UI elements on transparent backgrounds compress dramatically better as lossy WebP with alpha than as lossless PNG. A product photo that's 800 KB as PNG might be 120 KB as lossy WebP with alpha — same transparency, 85% smaller.

Replacing animated GIFs. Animated WebP files are typically 50-80% smaller than equivalent GIFs with full 24-bit color instead of GIF's 256-color limit. The visual improvement is dramatic, especially for animations with gradients or photographic content.

A single format that does everything. If you want one format for photos, graphics, and animations, WebP handles all three. JPEG can't do transparency. PNG can't do lossy compression or animation. GIF can't do more than 256 colors. WebP does it all.

When NOT to Use WebP

WebP is not the right choice in every situation:

Print workflows. Print pipelines expect TIFF or high-quality JPEG/PNG. WebP's 8-bit color depth and web-oriented compression are not designed for print reproduction. If your images go to a printer, use TIFF (16-bit, lossless) or PNG.

Archival storage. For long-term image archives, lossless formats with broad software support are safer bets. PNG and TIFF have decades of software support and standardization behind them. WebP is well-supported now, but PNG is a W3C standard with a 30-year track record.

When you need the absolute best compression. AVIF outperforms WebP by roughly 20% in file size at equivalent quality, with the bonus of 10/12-bit HDR support. If encoding speed is not a constraint and your audience's browsers support AVIF (97%+ in 2026), AVIF is the better choice for maximum compression. See What Is AVIF? for the details.

When you need 16-bit color depth. WebP maxes out at 8-bit per channel. Scientific imaging, medical imaging, and high-end photography workflows that require 16-bit precision should use PNG or TIFF.

Legacy system integration. Some older CMS platforms, email clients, and desktop applications still don't handle WebP. If your images will be opened in software from 2018 or earlier, JPEG or PNG is safer.

How to Convert Images to WebP

Using Pixotter (Browser-Based)

The fastest way to convert images to WebP without installing anything:

1. Open Pixotter's Convert tool.
2. Drop your images — JPG, PNG, HEIC, BMP, TIFF, GIF, or any other supported format.
3. Select WebP as the output format.
4. Adjust quality if needed (default 80 is a good starting point for photos).
5. Download your converted files.

Everything processes in your browser using WebAssembly. Your files never leave your device — no upload, no server, no waiting for a round-trip. Batch conversion works too: drop multiple files and convert them all at once.

Already have WebP files that are too large? Run them through Pixotter's Compress tool to reduce file size while keeping the WebP format.

Need to go the other direction? Pixotter also converts FROM WebP to JPG, PNG, and other formats — useful when you receive WebP files but need a different format for print, email, or legacy software. See How to Convert WebP to JPG for the full walkthrough.

Using the Command Line (cwebp)

Google provides cwebp (version 1.4.x) as part of the libwebp package for command-line conversion:

# Convert JPEG to lossy WebP at quality 80
cwebp -q 80 input.jpg -o output.webp

# Convert PNG to lossless WebP
cwebp -lossless input.png -o output.webp

# Convert with near-lossless mode (quality 90-100 range, slight lossy)
cwebp -near_lossless 60 input.png -o output.webp

Install on Ubuntu/Debian:

sudo apt install webp

Install on macOS:

brew install webp

The cwebp encoder is fast — a 12 MP image converts in under a second on modern hardware. For batch conversion, combine with find and shell scripting, or use Pixotter's batch conversion for a visual interface.

Frequently Asked Questions

What does WebP stand for?

WebP doesn't have an official expansion — Google named it as a play on "web" and the idea of a web picture format. It's pronounced "weppy" according to Google's documentation, though many people say "web-P."

Is WebP better than JPEG?

For web use, yes. WebP produces files 25-34% smaller than JPEG at equivalent visual quality, and adds transparency and animation support that JPEG lacks. The only scenarios where JPEG is preferable are legacy software compatibility and print workflows.

Can I open WebP files on my computer?

Yes. Windows 10+ (with the WebP Image Extension from Microsoft Store), macOS (Preview in macOS Big Sur 11+), and Linux (via libwebp and most modern image viewers) all support WebP natively. Chrome, Firefox, Safari, and Edge display WebP in web pages. For older systems, convert to JPEG or PNG using Pixotter's Convert tool.

Does WebP support transparency?

Yes — both lossy and lossless WebP support full 8-bit alpha channels. This is a significant advantage over JPEG (no transparency at all) and GIF (1-bit transparency only — each pixel is fully transparent or fully opaque). WebP's lossy-with-alpha mode is especially powerful: you get the small file sizes of lossy compression with the transparency of PNG.

Should I convert all my PNGs to WebP?

For web delivery, usually yes. Lossless WebP is 26% smaller than PNG with identical quality. If the images will only be served on the web and you don't need 16-bit color depth, WebP is the better format. For source files in design workflows, keep the PNGs as originals and export WebP for the web. Read the detailed comparison at PNG vs WebP.

Will WebP replace JPEG and PNG?

WebP is already the recommended format for web images, but "replace" is too strong. JPEG and PNG have decades of universal software support, established workflows, and use cases (print, archival) where WebP doesn't fit. What's more likely: WebP (and eventually AVIF) become the default for web delivery, while JPEG and PNG remain the standard for everything else. For help deciding which format fits your use case, see Best Image Format for Web.