Edit: What you can do is just upload an image then link it to the video instead or follow this:
1. Get the Youtube video link e.g. https://www.youtube.com/watch?v=Gc2en3nHxA4 (Remember this id Gc2en3nHxA4)
2. There are 4 a default thumbnail images to each video the, URL to these images will be like
https://img.youtube.com/vi/
https://img.youtube.com/vi/
https://img.youtube.com/vi/
3. Now to add or embed youtube video, add img tag and replace Youtube Video id
4. Now add URL tag and point URL to actual youtube video
5. Final result, Youtube video, click to play
https://img.youtube.com/vi/Gc2en3nHxA4/0.jpg