What Is WebP? Google's Image Format, Explained
What WebP Actually Is
WebP is a raster image format developed by Google and first released in 2010. It was built on the VP8 video codec — the same technology Google acquired when it bought On2 Technologies — and later extended with VP8L for lossless compression. The name is simply a portmanteau of 'Web' and 'P' (for picture). The core idea was straightforward: JPEG had been the dominant format for photographs since the early 1990s, and PNG had become the go-to for graphics with transparency, but neither was designed with modern web performance in mind. Both formats were showing their age in an era when page load speed directly affects search rankings, bounce rates, and ad revenue. Google, with an obvious interest in making the web faster, created WebP to replace both. Technically, WebP files use a container format based on RIFF (Resource Interchange File Format), which is the same container structure used by WAV audio files. Inside that container, the actual image data is compressed using either lossy or lossless algorithms, and the format also supports animation (a direct competitor to GIF and APNG) and alpha-channel transparency in both lossy and lossless modes. One detail that surprises many people: a lossy WebP file with transparency is possible. JPEG cannot do this at all — it has no alpha channel. WebP's ability to combine lossy compression with a transparency layer makes it particularly useful for product photography on e-commerce sites, where you want a white or transparent background but also need the file to be as small as possible.
How WebP Compression Works — and What the Numbers Mean
WebP's compression efficiency comes from several algorithmic techniques that go beyond what JPEG and PNG use. For lossy compression, WebP uses block-based prediction similar to H.264 video encoding. The image is divided into macroblocks (typically 16×16 pixels for luma, 8×8 for chroma), and each block's values are predicted from neighboring blocks that have already been encoded. Only the difference between the prediction and the actual values is stored. This predictive coding is far more efficient than JPEG's discrete cosine transform (DCT) alone, especially in areas with gradients or repeating textures. For lossless compression, WebP uses a combination of spatial prediction, color-space transformation, LZ77 backward references, and Huffman coding. The result: lossless WebP files are typically 26% smaller than equivalent PNGs, according to Google's own benchmarks on a corpus of 10,000 images. For lossy compression, the numbers are even more dramatic. Google's testing showed lossy WebP images are 25–34% smaller than comparable JPEG files at equivalent visual quality. Independent tests — including those run by Cloudinary and ImageMagick contributors — have generally confirmed savings in the 25–35% range, though the exact figure depends heavily on image content. Photos with lots of fine detail (grass, hair, fabric) compress less efficiently than images with smooth gradients. To put that in practical terms: if your product page loads 40 images averaging 120 KB each as JPEGs, switching to WebP could reduce that to roughly 80–90 KB per image, saving around 1.2–1.6 MB per page load. At scale — say, a site with 50,000 monthly visitors — that translates to terabytes of reduced bandwidth per year. Quality settings in WebP are expressed on a scale of 0–100, similar to JPEG. A quality setting of 80 in WebP generally produces visual results comparable to JPEG at quality 90–95, which is why most image optimization guides recommend WebP 75–85 as a reasonable default for web use.
Browser and Platform Support: Where Things Stand Now
When WebP launched in 2010, adoption was slow. Firefox resisted adding support for years, citing concerns about Google controlling a web standard. Safari on Apple platforms was notably absent from the support list until September 2020, when Safari 14 finally added WebP support alongside iOS 14. As of 2025, browser support is effectively universal for the core WebP feature set. Chrome (since version 9, 2011), Firefox (since version 65, 2019), Edge (since version 18, 2018), Opera, and Safari 14+ all support lossy and lossless WebP. The global browser support figure sits above 97% according to caniuse.com data. The platform picture is slightly more complicated: - **Windows**: WebP is natively viewable in Windows 11's Photos app. Windows 10 requires installing the WebP Image Extensions from the Microsoft Store (it's free). Older versions of Windows cannot display WebP natively without third-party software. - **macOS**: Preview on macOS 11 (Big Sur) and later opens WebP files without issue. Earlier versions do not. - **iOS/Android**: Both platforms support WebP natively in their system image viewers and browsers. - **Adobe software**: Photoshop added native WebP support in version 23.2 (released February 2022). Before that, users needed a plugin. Illustrator and InDesign still have limited or no native WebP support as of early 2026, which matters if you're working in print workflows. - **CMS platforms**: WordPress has supported WebP uploads since version 5.8 (July 2021). Shopify serves WebP automatically through its CDN when the browser supports it. The practical implication: if you're serving images on the web, you can almost certainly use WebP without a fallback for your main user base. If you're distributing images for offline use or print, the format still has meaningful compatibility gaps.
WebP vs. JPEG, PNG, and AVIF: Honest Comparisons
WebP is not the best format for every situation, and understanding where it falls short is as important as knowing where it excels. **WebP vs. JPEG**: For photographs displayed on the web, WebP wins on file size at comparable quality. However, JPEG has one significant practical advantage: it is supported by every device, operating system, and piece of software made in the last 30 years. If you're sending an image via email to someone who might open it on a 2015 MacBook with Safari 12, JPEG is the safer choice. WebP also renders slightly differently from JPEG at the same numeric quality setting — some photographers find WebP's compression artifacts (which tend to appear as subtle blockiness in fine-detail areas) less aesthetically acceptable than JPEG's more familiar artifacts. **WebP vs. PNG**: For images requiring transparency or pixel-perfect accuracy (logos, icons, screenshots of interfaces), lossless WebP is generally better than PNG — smaller file, same quality. The exception is when you need maximum software compatibility, such as embedding images in Word documents, PowerPoint presentations, or older design tools. **WebP vs. AVIF**: This is where WebP starts to look dated. AVIF, based on the AV1 codec, typically achieves 20–50% better compression than WebP at equivalent quality, and it handles high dynamic range (HDR) and wide color gamut images natively. Browser support for AVIF reached ~95% globally in 2024. For new projects, AVIF is increasingly the better technical choice. WebP's advantage is that it's more mature, has better tooling support, and encodes significantly faster than AVIF — AVIF encoding can be 10–20× slower, which matters if you're processing images in bulk. **WebP vs. GIF**: For animated images, WebP animation consistently produces smaller files than GIF (often 60–70% smaller) with better color depth (GIF is limited to 256 colors). The main reason GIF persists is cultural familiarity and near-universal support in messaging apps and older platforms.
Converting Images to and from WebP
There are several ways to convert images to WebP depending on your workflow and technical comfort level. **Command-line tools**: Google provides the official `cwebp` encoder and `dwebp` decoder as part of the libwebp library. A basic conversion looks like: `cwebp -q 80 input.jpg -o output.webp`. The `-q` flag controls quality (0–100). These tools are powerful but require a terminal and some familiarity with command-line interfaces. **ImageMagick**: The widely-used ImageMagick suite supports WebP conversion via `convert input.png -quality 85 output.webp`. ImageMagick is available on most Linux servers and can be scripted for batch processing. One caveat: ImageMagick's WebP output quality can differ from `cwebp` at the same numeric setting because they use different underlying encoding parameters. **Photoshop**: Since version 23.2, you can export to WebP via File > Export > Export As, then select WebP from the format dropdown. The dialog gives you quality and lossless options. Photoshop does not currently support WebP animation export. **Browser-based converters**: Services like CocoConvert let you upload a JPEG, PNG, GIF, or other common format and download a WebP file without installing anything. This is the fastest path for one-off conversions or for users who don't work with images regularly. CocoConvert supports converting to and from WebP for all major raster formats. It does not currently support converting WebP animations to video formats like MP4 — for that, you'd need a dedicated video tool like FFmpeg. **CMS and CDN automation**: Cloudflare, Cloudinary, and imgix can all convert images to WebP on-the-fly at the CDN level, serving WebP to supporting browsers and JPEG/PNG to others automatically. This is the most scalable approach for large websites but requires either a paid CDN plan or self-hosted infrastructure.
When You Should (and Shouldn't) Use WebP
WebP is a strong default choice for web images, but there are clear cases where it's the wrong tool. **Use WebP when**: - You're optimizing images for a website or web app and your audience uses modern browsers (which, in 2026, means virtually everyone). - You need transparency in a compressed image — lossy WebP with alpha is a genuine capability gap that JPEG cannot fill. - You're replacing GIF animations with something more efficient and don't need broad messaging-app compatibility. - You're working with a CMS or CDN that handles WebP conversion and fallback automatically. **Don't use WebP when**: - You're preparing images for print. Print workflows use CMYK color spaces; WebP only supports RGB. Sending a WebP file to a print shop will cause problems. - You need to edit and re-save an image multiple times. Like JPEG, lossy WebP degrades with each encode/decode cycle. Keep your master files in a lossless format (TIFF, PNG, or lossless WebP) and export to lossy WebP only as a final step. - You're distributing images to a general audience outside a web context — email attachments, file-sharing downloads, or documents. The compatibility gaps on older systems and non-browser software are real. - You're working with medical, scientific, or archival images where pixel-perfect fidelity is legally or professionally required. Use lossless formats (PNG, TIFF) for these. - Your workflow depends on metadata-heavy images. WebP supports Exif and XMP metadata, but some tools strip or mishandle it during conversion. If GPS coordinates, copyright fields, or color profiles are critical, verify that your conversion tool preserves them correctly.
The Bottom Line on WebP
WebP occupies a specific and useful position in the image format landscape. It is not the newest or most technically advanced format — AVIF and the emerging JPEG XL both surpass it in compression efficiency. But it is mature, well-supported, and genuinely effective at reducing image file sizes on the web without meaningful visual quality loss. For most web projects, switching from JPEG and PNG to WebP is one of the higher-return optimizations available. A 25–35% reduction in image payload size is significant, and unlike many performance improvements, it doesn't require changes to your application logic or infrastructure — just a different file format. The conversion process is no longer a barrier. Tools ranging from command-line encoders to Photoshop to browser-based services like CocoConvert make it straightforward to convert existing image libraries or set up workflows that produce WebP by default. The remaining honest caveats: WebP is not a universal format, it has real limitations in non-web contexts, and if you're starting a new project today with no legacy constraints, AVIF deserves serious consideration as an alternative. But for the majority of websites running on existing infrastructure, with existing image libraries, and serving audiences on modern browsers, WebP remains one of the most practical and impactful format choices you can make. If you have a folder of JPEGs or PNGs you want to convert, CocoConvert's WebP converter handles the common cases — single files, batch uploads, and converting WebP back to JPEG or PNG when you need broader compatibility. For more complex workflows like animated WebP or server-side automation, the libwebp command-line tools or a CDN-level solution will serve you better.