In some cases we have found that sites running the WordPress TwentyFifteen theme (or some other themes) may experience issues with full screen background images being distorted or showing a large white space on the left or right of the page image.
See an example of this issue below (white space is illustrated with red lines):
To fix this issue, you need to disable the CSS from the TwentyFifteen theme from rendering on LiveEditor pages. You must ensure you are using version 2.3.3.2 of OptimizePress or above to access the special support options inside OptimizePress.
To access these options, go to OptimizePress > Support > Disable Styles & Scripts > Theme Styles & Scripts and then tick the “CSS” box next to the TwentyFifteen theme option.
If you are not using the TwentyFifteen theme, you should try ticking the CSS option next to the theme you are using.