i.ytimg.com/vi/I4j4OGl_XHQ/maxresdefault.jpg
get-thumbnail option gives url to broken images. · Issue #402 · yt-dlp/yt-dlp · GitHub
の動画のサムネイル取得が思った以上に簡単だった件
] Thumbnail download fails completely if maxresdefault.jpg is not available · Issue #21588 · ytdl-org/-dl · GitHub
thumbnails extractor
thumbnails extractor