WebP Format Explained: Everything You Need to Know

Introduction

If you have ever downloaded an image from the web and found yourself staring at a .webp file you couldn't open, you are not alone. WebP is one of the most widely used image formats on the internet today, yet many people still find it confusing. It appears in Google search results, e-commerce product pages, social media feeds, and countless other places across the web.

In this article, we will break down everything you need to know about the WebP format: what it is, how it works, why websites love it, where it falls short, and how to convert WebP files when you need a more universally compatible format.

What Is WebP?

WebP is an image format developed by Google and first released in 2010. It was created with a single overarching goal: to make the web faster by reducing image file sizes without sacrificing noticeable visual quality. Images account for a huge percentage of data transferred on the web, so even a modest reduction in file size translates into faster page loads, lower bandwidth costs, and a better user experience.

Google derived WebP from the VP8 video codec that it acquired through the purchase of On2 Technologies. The format was designed as a direct replacement for JPG, PNG, and GIF, combining the strengths of all three into a single, more efficient container.

How WebP Works: VP8 and VP8L Codecs

Under the hood, WebP relies on two primary codecs for encoding image data:

• VP8 codec — Used for lossy compression. VP8 applies predictive coding, where each block of pixels is predicted based on previously decoded blocks, and only the difference (the residual) is encoded. This approach is similar to intra-frame compression in video, which is why it achieves excellent compression ratios for photographs and complex images.
• VP8L codec — Used for lossless compression. VP8L employs a variety of advanced techniques including spatial prediction of pixels, color space transforms, use of a color cache for recently seen pixels, LZ77 back-reference matching, and Huffman coding. The result is a lossless format that typically produces files 20-30% smaller than equivalent PNG files.

Both codecs are encapsulated in a RIFF-based container format, which also supports additional features like animation frames, alpha channels, and metadata.

Lossy vs Lossless WebP

One of WebP's standout advantages is that it supports both lossy and lossless compression within the same format. This is a significant distinction from JPG, which only supports lossy, and PNG, which only supports lossless.

Lossy WebP

Lossy WebP compression discards some image data that the human eye is unlikely to notice. Google's own studies have shown that lossy WebP images are 25-34% smaller than comparable JPG images at the same perceived quality level (as measured by the SSIM index). For photographs and images with gradual tonal transitions, lossy WebP is an excellent choice.

Lossless WebP

Lossless WebP retains every single pixel of the original image perfectly. According to Google's comparisons, lossless WebP files are typically 26% smaller than PNG files. This makes lossless WebP ideal for graphics, illustrations, logos, and any scenario where pixel-perfect reproduction matters.

WebP Features at a Glance

WebP is more than just a smaller image format. It comes packed with features that make it versatile:

• Animation support — WebP supports multi-frame animation, similar to GIF but with vastly superior compression. Animated WebP files can be up to 64% smaller than equivalent GIF files while supporting 24-bit color and 8-bit alpha transparency.
• Alpha transparency — Both lossy and lossless WebP support full alpha channel transparency. Lossy WebP with alpha is particularly noteworthy because JPG has no transparency support at all. This means you can have a small, lossy-compressed photo with a transparent background.
• Metadata support — WebP files can contain EXIF metadata (camera settings, GPS data), XMP metadata (editing history, copyright), and ICC color profiles, ensuring proper color management across displays.
• Progressive decoding — WebP supports incremental decoding, which allows browsers to render a lower-quality preview while the full image is still loading.

File Size Advantages Over JPG and PNG

The primary reason websites adopt WebP is file size savings. Here is what you can typically expect:

• Lossy WebP vs JPG: 25-34% smaller at equivalent visual quality.
• Lossless WebP vs PNG: 26% smaller on average.
• Animated WebP vs GIF: Up to 64% smaller with much better color depth and transparency.

For a website serving millions of images per day, these savings compound dramatically. They reduce bandwidth costs, improve page load times, and boost Core Web Vitals scores, which directly affect search engine rankings.

WebP Limitations

Despite its strengths, WebP is not without drawbacks:

• Older software incompatibility — Many desktop applications, particularly older versions of image editors like Photoshop (before version 23.2), GIMP (before version 2.10), and Microsoft Office, cannot open or insert WebP files natively. This can be frustrating when you download an image from the web and need to use it in a document or presentation.
• Limited support in email clients — Most email clients, including Outlook and older versions of Apple Mail, do not render WebP images inline. If you embed a WebP image in an email, recipients may see a broken image or a download link instead.
• Social media platform restrictions — While some social media platforms accept WebP uploads, others silently convert them or reject them outright. This inconsistency can be confusing for users.
• Maximum resolution — The VP8 lossy codec limits images to 16,383 x 16,383 pixels. While this is more than sufficient for web use, it may not meet the needs of extremely high-resolution print workflows or scientific imaging.
• Lossy recompression — Like any lossy format, repeatedly editing and saving a lossy WebP file will degrade quality over time. For editing workflows, it is better to keep source files in a lossless format.

Browser Support Status

WebP browser support has reached near-universal levels. As of 2026, all modern browsers fully support WebP:

• Google Chrome — Full support since version 32 (2014).
• Mozilla Firefox — Full support since version 65 (2019).
• Apple Safari — Full support since version 16 on macOS and iOS (2022).
• Microsoft Edge — Full support since it moved to the Chromium engine (2020).
• Opera, Brave, Vivaldi — Full support through their Chromium base.

The only notable holdout was Internet Explorer, which Microsoft officially retired. Today, WebP works in over 97% of active browsers worldwide, making it safe to use as a primary web image format.

When to Use WebP

WebP excels in the following scenarios:

• Website images — If you are building a website and want the best balance of quality and file size, WebP is the top choice. It reduces bandwidth and improves page speed.
• Web applications — Progressive web apps and single-page applications benefit from smaller asset sizes, which means faster initial loads and less memory usage.
• Animated content — If you are using GIFs for short animations, switching to animated WebP will dramatically reduce file sizes while improving quality.
• Transparent images for web — When you need transparency in a lossy-compressed image (something JPG cannot provide), lossy WebP with alpha is the answer.

However, if your workflow involves sharing images with people who may use older software, or if you need to embed images in emails and documents, you may want to convert your WebP files to JPG or PNG for maximum compatibility.

Converting WebP to JPG or PNG

There are many situations where you need to convert a WebP file to a more universally compatible format. Perhaps you downloaded a product image from a website and need to insert it into a Word document, or you want to share a photo via email without worrying about whether the recipient's email client supports WebP.

The most convenient and privacy-friendly way to convert WebP files is to use a browser-based converter that processes files locally on your device. Unlike server-based converters that require you to upload your images to a remote server, a client-side tool keeps your files on your computer at all times.

OpenedFile's WebP to JPG/PNG Converter does exactly this. It runs entirely in your browser using JavaScript and the HTML5 Canvas API, so your images are never uploaded anywhere. Simply drag and drop your WebP file, choose your target format, and download the converted file instantly.

Conclusion

WebP has matured from a Google experiment into the dominant image format on the modern web. Its combination of lossy and lossless compression, animation support, alpha transparency, and impressive file size savings make it an ideal choice for web developers and anyone publishing content online.

That said, WebP is not perfect for every situation. Older software, email clients, and certain workflows still require JPG or PNG. When you encounter a WebP file that you need in a different format, a fast and private browser-based converter is the best solution. Understanding the format and knowing when to convert gives you the flexibility to work efficiently in any context.