i.ytimg.com/vi/_HYhAc_bPgk/hqdefault.jpg?sqp=-oaym

All about Thumbnail Images as ytimg maxresdefault especially in Search

get-thumbnail option gives url to broken images. · Issue #402

All about Thumbnail Images as ytimg maxresdefault

php - How do I get a video thumbnail from the API

php - How do I get a video thumbnail from the API? - Stack Overflow

thumbnail has different resolutions after subsequents API

thumbnail grabber - Boing Boing

API — getting video thumbnail · GitHub