A less elegant option, but one that saves space, is to rely on live YouTube links for playback. Here is an approach to do this:
- Play the video (in the highest resolution possible) and pause it at the moment you want to use for the placeholder image.
- Take a screen shot and paste the image into your slide
- Draw a big triangle and place it in the middle of your still image as a play button
- Insert the hyperlink to the YouTube video inside the triangle and you are done.
By default, the video will play in the standard YouTube view with all the screen clutter around it. Here is a way to get a link that triggers a full screen view of a YouTube video.
The standard format of a YouTube URL is this: http://www.youtube.com/watch?v=R55e-uHQna0. Here is the trick. Replace the watch?v= bit with this v/ to get this result: http://www.youtube.com/v/R55e-uHQna0. Make this the link your play back triangle points to.