VTEX stores already have automatic image compiling to WebP format, as reported in this previous announcement. The news is that this process is now lossless for PNG files. This means that images with this file extension will still be converted to the Google's format, but without quality losses.
The conversion of the image files only happens when your store is accessed by someone using a compatible browser (e.g. Gooogle Chrome). If they use a browser that doesn't read the format, the images won't be converted and will be displayed in their original formats. Notice that this automatic image compiling doesn't affect the file you uploaded in the CMS, only the way it's rendered on screen.
This change was developed to meet the needs of users who really have to display high quality images on their stores, even after the conversion to the WebP format. In all other situations, using .jpg files still is the best solution to keep your website's performance.