I just wrote myself a small tool to get all the thumbnail images available for a YouTube video.
Say you have a Youtube URL, the ID is the last part: https://www.youtube.com/watch?v=GDukVqBDd3Q, in this case
GDukVqBDd3Q. Just copy this into the tool and you will get all the images available. You can choose to get JPG or WebP images and you can click each to see it or right-click to save it.
If you feel like doing this by hand, here are the different URLs:
- Player Background Thumbnail (480x360):
- Video frames thumbnails (120x90)
- Lowest quality thumbnail (120x90)
- Medium quality thumbnail (320x180)
- High quality thumbnail (480x360)
- Standard quality thumbnail (640x480)
- Unscaled thumbnail resolution