Finding a Thumbnail from a Youtube video

So I needed to get thumbnails of the youtube videos to make the media bar slider work in the Chameleon theme of an Elegant Theme. I linked the video in the theme’s custom fields and then uploaded a jpg image from the youtube video into the media library. Then added the image URL from my media library to the custom field for image. It’s complicated, I know, but eventually it works.

 
 
img.youtube.com/vi/(insert video # here)/0.jpg
 

Elegant Themes Chameleon Media Bar- not showing videos