Is there any way to setup an image (thumbnail) so that when people click on it the an embedded youtube video plays in the lightbox instead of the bigger thumbnail image?
Hey Carlos,
The thread below discusses about how to do just that. Read through and let us know if you any questions! 
http://forum.wpbeaverbuilder.com/support/q/video-lightbox/
Ben
Thank you Ben ! This is very helpful!
Hey Carlos,
No worries! Got that bookmarked as I knew a post like this was coming. Have fun with BB!
Ben