Choosing right thumbnail for your post or video is very important
It is very important to choose a very attractive and eye-catching thumbnail for your blog post or for your videos. I have noticed the videos that are getting more views just because of an interesting thumbnail. You can check the value of thumbnail over Youtube.
Thumbnail is more important than the content in the video. I have seen many videos don't have the same content that was shown in thumbnail but it gets a lot of traffic just because of that thumbnail.
So always try to choose a hottest favorite thumbnail.