What Is the WebP Image Format, and How Does It Compare to Traditional Formats Like JPEG and PNG in Terms of Size and Quality?


The WebP image format, developed by Google, offers superior compression modes for both lossy and lossless images when compared to traditional formats like JPEG and PNG. WebP aims to provide a balance of image quality and smaller file size, making web pages faster and more efficient. Below is an in-depth analysis of WebP's features and its comparison with JPEG and PNG formats.

Introduction to WebP

WebP is a modern image format introduced by Google in 2010. It supports both lossy and lossless compression within a single file, making it versatile for different types of images. WebP also supports features such as transparency (alpha channel) and animation, which were previously addressed by separate formats like PNG (for transparency) and GIF (for animations).

Lossy Compression

Lossy WebP compression works by discarding some of the image data to reduce file size, similar to JPEG. However, it uses more advanced compression algorithms, such as predictive coding based on the WebM video format, which leads to smaller file sizes with comparable or better image quality.

Lossless Compression

Unlike lossy compression, lossless WebP preserves all the original image data, ensuring no loss of quality. It achieves this through techniques such as image fragments and local entropy coding, which can compress files more efficiently than PNG while maintaining image integrity.

Comparison with JPEG and PNG

File Size

  • WebP vs JPEG: WebP's lossy compression can yield file sizes that are approximately 25-34% smaller than equivalent JPEG images at comparable quality levels. This is achieved through more efficient entropy coding and better prediction models.
  • WebP vs PNG: In terms of lossless compression, WebP files are generally 26% smaller than equivalent PNG files, thanks to its advanced compression algorithms.

Source: WebP Compression, 2023

Image Quality

  • WebP vs JPEG: WebP typically offers better image quality at the same file size when compared to JPEG. The advanced compression algorithms used in WebP preserve more image details and reduce artifacts such as blockiness.
  • WebP vs PNG: Because PNG is a lossless format, the quality remains unchanged. WebP’s lossless compression also ensures no loss of quality while maintaining smaller file sizes. However, in the case of lossy WebP, fine-tuned compression can achieve high visual fidelity that matches or exceeds PNG for certain applications.

Source: WebP Study, 2022

Transparency and Animation Support

  • Transparency: Both WebP and PNG support transparency, but WebP can offer smaller file sizes with either lossy or lossless transparency compared to PNG.
  • Animation: WebP supports animated images (similar to GIFs), but with better compression and quality. Animated WebP files are generally more efficient and provide smoother animations compared to GIFs.

Source: WebP Container, 2023

Advantages and Adoption

Performance Benefits

The smaller file sizes of WebP images can lead to faster page loads and lower storage costs, ultimately enhancing user experience, particularly on mobile devices and slower internet connections. This performance boost is crucial for web performance metrics such as Largest Contentful Paint (LCP) and Core Web Vitals.

Source: Optimize LCP, 2023

Wide Adoption

As of now, all major web browsers, including Google Chrome, Firefox, Microsoft Edge, and Safari, support WebP. Additionally, a growing number of image editing tools and online platforms, such as WordPress and CMS systems, have integrated WebP support.

Source: Can I use WebP


Overall, WebP stands out as a highly efficient image format offering significant benefits over traditional formats like JPEG and PNG. With better compression rates for both lossy and lossless images, smaller file sizes, and maintaining high image quality, WebP can enhance web performance and user experience extensively. As browser and tool support continue to grow, adopting WebP is becoming increasingly beneficial for web developers and content creators aiming to optimize their digital content.