Q. My ebooks are not displaying properly in Ebook Central - only showing plain text

The lack of images and text formatting in these ebooks can be brought about by a enabling the Accessibility mode in Ebook Central. You can disable this again by going to the menu in the top right and following Setting > Profile > select Disable Accessibility Mode > tick Accept T&C > Save.

You can set accessibility mode in a browser too, which could also influence how Ebook Central renders its content. How to toggle this mode varies from browser to browser.