Download the YouTube thumbnail in 480 × 360
480 × 360 is hqdefault, the one resolution that exists on absolutely every video: if maxres or sd are missing it is because the video was uploaded without them, but this one is always there. It is what listings and small thumbnails use.
YouTube is a trademark of Google; CreativeStar is not affiliated with Google. Thumbnails belong to their creators: use them as reference or with permission.