**We have tuned up many stores under this service, and in every case we have improved the Desktop score to over 85 (which is rated as ‘Good’ and displays a green badge). In some cases the mobile score can’t be improved quite as high as 85. This is usually because we can’t get access to some of the theme files. Each time this has happened we have improved the mobile score to at least 75 (typically from a Poor/red score of ~50 or less).
To maintain the high score we achieve you must continue to use optimised images. For more information, please see this article on our blog.