Wow, thanks for the fast response.
So, basically, I or users have to upload a picture that is totally irrelevant to the target youtube video thumbnail, right?
It would be really nice, if the plugin has the function that takes youtube link and then extract thumbnail of the vid, store it on media library, and then display in grid.
One more question is that I saw your demo page, and those vids do not even have thumbnails. How can you do that if you always have to upload or select a dummy image for linking an youtube vide??