Hi,
Sorry for the misunderstanding. Your explanation a very unclear. Moreover, it is not from our demo. If you want to make your image larger on mobile devices, try to add some padding to the column with this image set as a background.
The image has it’s height because you have set “Equal height” for the row containing this image. But it doesn’t work this way for mobile devices. And it is not our theme issue. It is how Visual Composer works. Just add some content to this column or add some extra padding.
Kind Regards
Xtemos