What Is WebP? Why Google Created It and When to Use It

WebP is an image format developed by Google and released in 2010. Its goal was simple: produce the same visual quality as JPG and PNG at significantly smaller file sizes, reducing the bandwidth required to serve web images. It achieved that goal and has since become the dominant image format served by Google Search, YouTube, Facebook, and most major CDNs.

Why Google Created WebP

In 2010, Google published research showing that JPG images — which had been the web standard since 1992 — were consuming an outsized share of web page bytes. Images were the largest category of page weight, and JPG's compression algorithm, while excellent for its time, had not advanced in nearly two decades.

Google's solution was a new format based on the intra-frame encoding from VP8, their open-source video codec. The key insight: video codec technology had advanced enormously since 1992 and could achieve much better compression of still images than the DCT-based algorithm inside JPEG.

The result: WebP delivers 25–34% smaller files than JPG at equivalent visual quality and 26% smaller files than lossless PNG.

How WebP Compression Works

WebP uses two distinct compression modes:

Lossy WebP (for photographs and complex images)

Based on the VP8 intra-frame prediction algorithm. It divides the image into macroblocks and predicts the pixel values of each block from its neighbours. Only the difference between prediction and actual pixel values is stored, not the values themselves. This prediction step eliminates enormous amounts of redundant data.

Lossless WebP (for logos, graphics, screenshots)

Uses a combination of spatial prediction (similar to PNG's filter modes) plus entropy coding and a colour transformation step. The result is 26% smaller than equivalent PNG files with identical visual output.

Transparency (Alpha Channel)

WebP supports transparency in both lossy and lossless modes. The alpha channel is compressed separately using a lossless algorithm regardless of whether the main image is lossy or lossless.

Browser and Software Support

Global browser support is approximately 97%, making WebP safe to use on any modern site without fallbacks. For the 3% using older browsers, a JPG fallback served via the HTML <picture> element is standard practice.

WebP vs JPG vs PNG: Size Comparison

At quality 85 (1920 × 1080 photograph):

When WebP Is the Right Choice

• Any image served on a website — WebP is universally supported in modern browsers and reduces bandwidth costs
• E-commerce product images — smaller images load faster, reducing bounce rate and improving conversions
• Blog images and hero images — the largest image elements on most pages; WebP has the greatest impact here
• Mobile web — smaller files are especially valuable on cellular connections

When WebP Is Not the Right Choice

• Print production — most print shops do not accept WebP. Use JPG (Q95+) or TIFF.
• Microsoft Office (pre-2019) — older Office versions cannot render WebP inline
• Email clients — Outlook on Windows does not support WebP in email HTML
• Archival — use TIFF or PNG for archival; WebP (lossy mode) permanently discards data

Animated WebP

WebP supports animation, making it a modern replacement for animated GIF. An animated WebP file is typically 64% smaller than an equivalent animated GIF with better colour depth (WebP supports full 24-bit colour; GIF is limited to 256 colours).