Hi,
Fancybox added support for small screens by removing the top border (and bottom if no caption).
See here for example:
codepen.io/fancyapps/pen/pxovaa
Notice how the image stretches to the edge of the screen when viewed on a mobile in landscape
If you look at your own demo page, you can see that ARI Fancy Lightbox doesn't use the whole of the screen, but still has a huge border around the whole image
wp-quiz.ari-soft.com/plugins/wordpress-fancy-lightbox.html
Your plug-in uses FancyBox, so do you have any plans to update it, in line with the improvements that have made to recent editions of Fancy-box? Or maybe you can suggest a work-around?
I hope so, because yours is a good plug-in.
Regards,
Vinner