WebP.

WebP is an image format developed by Google for the web. It stores photos, graphics with transparent backgrounds, and even animations in smaller files than the well-known JPEG, PNG, or GIF formats. This matters for your business because images usually make up the largest portion of a webpage. Our Cologne-based Crafts Website Report found an average page size of 1.55 MB across 734 websites analyzed. Every kilobyte saved reduces load time, especially on cell phones with mobile data connections.

How WebP Works

WebP supports two types of compression: lossy and lossless. The lossy variant is intended for photos. According to Google, it predicts the content of a pixel block based on its neighboring blocks and stores only the difference, using the same principle as the VP8 video codec. The lossless variant precisely reconstructs every pixel and is suitable for logos, icons, and screenshots.

According to Google, lossless WebP files are 26% smaller than PNGs, while lossy WebP files are 25 to 34% smaller than comparable JPEG images at the same measured quality. Transparency works in both variants. According to Google, the format is supported by Chrome, Firefox, Edge, Opera, and Safari (version 14 and later).

What Your Business Should Keep in Mind

Start with the large photos. The cover photo at the top of the homepage, portfolio galleries, and team photos offer the biggest savings. Google provides a free tool called cwebp for converting images. Even so, we often see in projects that camera images—some several megabytes in size—end up on the website without being modified.

Reduce the image dimensions before changing the format. A photo that’s 6,000 pixels wide will still be too large for a cell phone screen, even as a WebP file. The format is one factor; the right size is another. You can also use lazy loading to load images further down the page only when the user scrolls.

Be sure to provide alternative text for every image. Whether Google and screen readers can understand what’s in the image doesn’t depend on the file format. The alt text makes this possible, regardless of whether the image is in JPEG or WebP format.

Keep the originals. Lossy compression permanently discards image data. You'll need the original file for printing, trade show displays, or a future redesign.

Frequently Asked Questions About WebP

Does Google display WebP images in search results? Yes. According to Google Search Central, Google Search supports images in the following formats: BMP, GIF, JPEG, PNG, WebP, SVG, and AVIF. It's important that the file extension matches the actual file type.

What about browsers that don't support WebP? According to Google, you can use the `picture` element to provide multiple versions of the same image. The browser will use the first one it can display; a standard `img` element serves as a fallback.

Can WebP replace animated GIFs? According to Google, yes. Animated WebP files support lossy and lossless compression as well as transparency, and can be smaller than GIF or APNG files.

The Speed Check shows you how much your images weigh and what that means for loading times.