It is possible to get the video thumbnail by using the id of that video in youtube. By using the id of the corresponding youtube video it is possible to display the thumbnail of that video where ever we want.
You can copy the url of the youtube video from the address bar of your browser For example :
https://www.youtube.com/watch?v=hc--xbxqNXI
Here the id of the video is one that is after “?v=” in the url, ie : “hc–xbxqNXI”
Copy the id and place it in the url below, you will get the images of that video
Usually YouTube video has 4 generated images for each videos with different sizes. They are:
http://img.youtube.com/vi/insert-video-id-here/1.jpg
http://img.youtube.com/vi/insert-video-id-here/2.jpg
http://img.youtube.com/vi/insert-video-id-here/3.jpg
http://img.youtube.com/vi/insert-video-id-here/default.jpg
These are the default thumbnail images and with different screenshots.
For the full size image use this
http://img.youtube.com/vi/insert-video-id-here/0.jpg
There medium quality version of the thumbnail image use
http://img.youtube.com/vi/insert-video-id-here/mqdefault.jpg
For the standard version of the thumbnail image use
http://img.youtube.com/vi/insert-video-id-here/sddefault.jpg
For the high quality version of the thumbnail image use
http://img.youtube.com/vi/insert-video-id-here/hqdefault.jpg
If you want the maximum resolution image use
http://img.youtube.com/vi/insert-video-id-here/maxresdefault.jpg
nice article