I’m interested in adding a ‘retina’ logo to the header of my website, http://iflewtoeurope.com/ . As you can see currently, the logo is there, but it appears blurry on retina and HiDPI screens. There appears to be no way to upload a logo at this ‘double density’ via the Customise menu, and the plugins I’ve tried such as WP Retina 2x don’t work for me either.