If you get this warning, and you do not have CDN available and as a feature, you should either enable or activate this feature.  The Pegasaas image CDN automatically serves the WebP next-generation image format to supporting web browsers.

If you already do have the Pegasaas image CDN active and are still getting this warning, it may be that the image that is being flagged as not being served in a next-generation format is likely being injected into your page via JavaScript by your theme or one of your plugins.

Unfortunately at this time, Pegasaas Accelerator is unable to map image locations to the image CDN for image that are injected into the web page via JavaScript.