i.ytimg.com/vi/BfqeEkZiaUs/maxresdefault.jpg

Heaven's War - DVD –

i.ytimg.com/vi/I4j4OGl_XHQ/maxresdefault.jpg

All about Thumbnail Images as ytimg maxresdefault especially in Search

i.ytimg.com/vi/I4j4OGl_XHQ/maxresdefault.jpg

php - Fetch highest thumbnail resolution - Stack Overflow

Getting all the video thumbnails from a video

thumbnails extractor

thumbnail link doesn't work in all cases - Stack Overflow