What are WebP images and How to view them in Windows

Google continues to innovate with new ideas and new thinking about the web. Other times they acquire companies and then develop their technologies further. On2 Technologies was purchased by Google and the WebP image format was part of that acquisition.

WebP images can currently be viewed inside Google Chrome and Opera web browsers, plus a number of graphics viewers and graphics editors. There is also a WebP codec file that can be installed in Windows in order to view WebP images within Windows Explorer.

WebP images can be seen in the image previews in the Google Play Store. Save a screen capture shown in the app preview area and you will quickly see this curious new .webp format. Usually, opening up the graphic file will cause either Google Chrome or Opera to open in order to display the .webp image file. Windows doesn't yet natively support the WebP file format because it is just that new.

How is WebP Image Format Different?

The WebP format can provide either lossless or lossy compression for images. That is to say, either images will be saved without any perceived loss of quality or they will have some degree of quality loss. A WebP lossless image converted from a PNG image file will be approximately 26 percent smaller in file size. A JPEG file, which is a lossy image format, will usually be 25-34 percent smaller once converted to a WebP image format.

Lossless transparency images, sometimes called alpha channel, is supported since Google placed an emphasis on this development back in 2011. Lossless transparency requires only 22 percent extra bytes of storage needed to achieve it. Transparency can also be used with the lossy compression included and can reduce the file size down by up to three times when using compression on blue, green and red color channels.

Google has also since cited WebP as a possible alternative to animated GIF files because the WebP image format can support 24-bit color with transparency. The animated WebP file can include both lossy and lossless frames which is highly unusual. A file reduction size of 64 percent for conversion from animated GIF to lossy WebP and a 19 percent file size reduction when sticking to lossless image quality has been mentioned by Google. 

How WebP Gets The Image Files Smaller

The WebP compression makes use of predictive coding when encoding the original image. The neighboring pixel is predicted and then the variance between the prediction and the actual pixel detail is stored. The more accurate the prediction, the less data is needed to store the image.

Using the residual method for storing images therefore contains many zero values which compress better. The compression method can use image fragments to save space if they are a pattern that is repeated in an image. A local palette of recent colors seen in the image can also be used to reduce the data required if the same colors repeat too.

The compression mode is called VP8L. It shares some similarities to the LZ77 compression algorithm. A WebP file includes both VP8 and VP8L image data, plus a container based on RIFF container.

Are WebP Image Files Gaining Acceptability?

WebP files are still pretty new and many people are not aware of them. To be fair, most internet users wouldn't notice any difference with a switch from one image format to another anyway. However, they would notice the increased speed that web pages are delivered to their web browser but they would not necessarily appreciate one of the root causes for this is WebP images usage.

As users update their web browsers to newer versions (which can take a few years as most internet users are extremely slow to update) support for the WebP image format will continue to grow.

Image editors and image viewers are already incorporating the WebP image format in many cases. The XnView image viewer application was one of the first to support the nascient format. For a quick conversion, you can use our own online converter to convert WebP files to JPEG or to PNG and then share them with someone whose system doesn't support the WebP image format yet. If you are on Android, we've got a guide for how to Batch convert BMP, JPG, GIF, PNG, WebP images from one format to another there, as well.

HEIC vs. WebP

Apple started using the HEIF (HEIC) image format last year, a format which also reduces image size greatly, so we'll now have to see how the two formats evolve, either side by side or one of them gaining wider support over the other. It would also be interesting to see if either WebP or HEIC will actually be able to replace JPG at some point.

If you are using the WebP format and you'd like to convert HEIC files to WebP, our online converter can do that as well - simply use the HEIC to WebP page.