What Is WebP? Complete Guide to Google's Modern Image Format
WebP is a modern image format developed by Google and first released in 2010. It provides superior compression for both lossy and lossless images compared to JPG and PNG, typically producing files 25-35% smaller at equivalent visual quality. WebP also supports alpha channel transparency and animation in a single format, making it a versatile replacement for JPG, PNG, and GIF in web applications.
Technical Overview of the WebP Format
WebP is based on the VP8 video codec technology for lossy compression and uses a prediction-based approach for lossless compression. In lossy mode, WebP applies block prediction: each block of pixels is predicted from previously decoded blocks, and only the difference (residual) is compressed using a transform similar to DCT. This prediction step gives WebP a significant advantage over JPG, especially in areas with gradual color changes. For lossless compression, WebP uses a combination of advanced techniques including spatial prediction of pixels, color space transformation, backward reference to recurring patterns, and entropy coding with an arithmetic coder. WebP supports 8-bit color depth per channel (24-bit RGB or 32-bit RGBA) and images up to 16,383 by 16,383 pixels. The format uses the RIFF container structure, allowing metadata and ICC color profiles to be embedded. WebP's lossy mode supports adjustable quality from 0 to 100, while lossless mode optimizes automatically for the smallest possible file without any quality loss.
Advantages and Limitations of WebP
WebP combines the best features of JPG, PNG, and GIF into a single format, though it does have some trade-offs.
- Lossy WebP produces files 25-34% smaller than JPG at equivalent SSIM quality index
- Lossless WebP produces files 26% smaller than PNG on average
- Supports alpha channel transparency in both lossy and lossless modes
- Supports animation as an alternative to GIF, with much better compression and color depth
- Supported by all major modern browsers including Chrome, Firefox, Safari, and Edge
- Maximum image dimensions limited to 16,383 x 16,383 pixels, smaller than JPG or PNG limits
- Limited support in some older image editing software and legacy systems
- Color depth limited to 8 bits per channel, lacking the 16-bit support of PNG and TIFF
- Not universally accepted for print workflows where TIFF or high-quality JPG are preferred
WebP vs JPG vs PNG: How They Compare
Understanding how WebP stacks up against established formats helps you decide when to adopt it.
| Feature | WebP | JPG/PNG |
|---|---|---|
| Lossy compression | 25-34% smaller than JPG | JPG: baseline lossy standard |
| Lossless compression | 26% smaller than PNG | PNG: baseline lossless standard |
| Transparency | Yes, with lossy or lossless | PNG only; JPG has none |
| Animation | Yes, superior to GIF | Neither JPG nor PNG (APNG limited) |
| Max dimensions | 16,383 x 16,383 px | JPG: 65,535 px; PNG: 2.1 billion px |
| Browser support | All modern browsers (since ~2020) | Universal, including legacy browsers |
| Editing software | Growing but not universal | Universal support everywhere |
Best Use Cases for WebP
- Website images where smaller file sizes directly improve page load speed and Core Web Vitals
- E-commerce product images that benefit from lossy compression with optional transparent backgrounds
- Progressive web apps and single-page applications optimizing for bandwidth
- Animated content on the web as a superior replacement for GIF files
- Mobile web experiences where bandwidth and data usage are critical concerns
- Content delivery networks (CDNs) that serve optimized images based on browser capabilities
- Social media and messaging platforms that prioritize fast image delivery
How to Convert Images to WebP
- 1
Choose your source image
WebP works as a target format for JPG, PNG, GIF, and other image types. Select the images you want to optimize for web delivery.
- 2
Upload to WeLoveConvert
Use the WeLoveConvert online tool to upload your images. The conversion happens entirely in your browser, keeping your files private and secure.
- 3
Configure WebP settings
Choose between lossy mode for photographs (quality 75-85 recommended) or lossless mode for graphics. If your source has transparency, it will be preserved automatically.
- 4
Download and implement
Download the converted WebP files and implement them on your website. Consider using the HTML picture element to provide JPG/PNG fallbacks for maximum compatibility.
History of WebP and Browser Adoption
Google announced WebP in September 2010 as part of its effort to make the web faster. The format was derived from the VP8 video codec that Google had acquired through its purchase of On2 Technologies. Initially, WebP only supported lossy compression, but Google quickly added lossless compression, transparency, and animation support by 2011-2012. Browser adoption was slow at first: Chrome supported WebP from the start, and Opera followed in 2011, but Firefox and Safari held out for years. Firefox added WebP support in 2019, and Apple finally added Safari support in 2020 with macOS Big Sur and iOS 14. This milestone meant WebP became usable as a primary web format without requiring fallbacks for most users. Today, WebP is supported by over 97% of web browsers globally. Major platforms like Facebook, YouTube, and eBay use WebP extensively, and content management systems like WordPress generate WebP versions of uploaded images by default. The format has become the de facto standard for optimized web images alongside the emerging AVIF format.
Frequently Asked Questions
What is WebP and who created it?
WebP is a modern image format created by Google in 2010. It was designed to provide better compression than JPG and PNG for web images, reducing page load times and bandwidth usage while maintaining high visual quality.
Do all browsers support WebP?
Yes, as of 2020 all major browsers support WebP, including Chrome, Firefox, Safari, Edge, and Opera. WebP is supported by over 97% of browsers globally. For the rare legacy browsers that do not support it, you can use the HTML picture element to provide JPG or PNG fallbacks.
Is WebP better than JPG?
For web use, WebP generally produces files 25-34% smaller than JPG at the same visual quality. However, JPG has wider compatibility with older software, higher maximum image dimensions, and is the standard for photography workflows. WebP is better for web delivery, while JPG remains important for interoperability.
Does WebP support transparency?
Yes, WebP supports full alpha channel transparency in both lossy and lossless modes. This makes it unique among formats: you can have a compressed photograph with a transparent background, something impossible with JPG and previously requiring PNG (at larger file sizes).
Can WebP replace GIF for animations?
Yes, animated WebP is significantly better than GIF. WebP animations support 24-bit color (16.7 million colors versus GIF's 256), alpha transparency, and much better compression. An animated WebP file is typically 50-90% smaller than an equivalent GIF.
What are the disadvantages of WebP?
WebP has a maximum dimension of 16,383 pixels per side, limited to 8-bit color depth, and is not widely supported in professional print workflows. Some older image editors cannot open WebP files natively, and email clients have inconsistent support for the format.
How do I open a WebP file?
Most modern web browsers can open WebP files directly. On Windows 10 and later, WebP is supported natively in the Photos app and File Explorer. On macOS Big Sur and later, Preview and Quick Look support WebP. For older systems, you can convert WebP to JPG or PNG using an online tool like WeLoveConvert.
Should I convert all my website images to WebP?
Converting to WebP is recommended for web images to improve page speed and reduce bandwidth. Use lossy WebP for photographs and lossless WebP for graphics with sharp edges or transparency. Provide JPG/PNG fallbacks using the HTML picture element for maximum compatibility.
WebP has matured from a Google experiment into the modern standard for web images, offering the best balance of compression efficiency, feature set, and browser support. By combining lossy and lossless compression, transparency, and animation in a single format, WebP simplifies image optimization for web developers. While it does not replace JPG and PNG in all contexts, WebP is the optimal choice for web delivery where page speed, bandwidth efficiency, and visual quality all matter.