How do I change the size of the videos in the lightbox?
You need to add the desired width and height to the video URL. For example for a YouTube video with the URL http://youtu.be/oeuHxC1cF0o
you would add the following to the end of the URL &width=500&height=250
to give http://youtu.be/oeuHxC1cF0o&width=500&height=250
. This will give you a video with a width of 500px and a height of 250px.