A .WEBP file (pronounced 'weppy') is an image file format created by Google, designed to improve the performance of web pages and make the web faster by reducing image file sizes.
The .WEBP format is based on an open-source compression algorithm called 'VP8' and uses a container based on RIFF.
The format is lossy, meaning some data is lost during encoding - repeated editing of a .WEBP file will reduce the overall quality of the image.
Google estimates 65% of current internet traffic is image and photo data, so a significant decrease in the amount of data sent across the web would increase overall speed for all internet users.
The Webp format faced minor criticism for not including common features such as transparency (alpha channel) from the outset, although Google announced additional features would be added at a later date.