An application I\'m working on needs to get HQ YouTube thumbnails given a URL. Using this answer, I tried using the maxresdefault.jpg
to get the maximum resolut
Update 2015 : None of your 'maxresdefault' link seems to be working
Try these:
http://img.youtube.com/vi/<insert-youtube-video-id-here>/0.jpg
http://img.youtube.com/vi/<insert-youtube-video-id-here>/1.jpg
http://img.youtube.com/vi/<insert-youtube-video-id-here>/2.jpg
http://img.youtube.com/vi/<insert-youtube-video-id-here>/3.jpg
Update 2019 ::
https://i.ytimg.com/vi/<insert-youtube-video-id-here>/hqdefault.jpg
Seems to return highest possible image....
1.jpg, 2.jpg, 3.jpg return previews through the length of the clip which are handy also ;)
As I understand it, YouTube only generates high-res stills for high-res videos. The first one you link was uploaded at a resolution of at least 1080p, while the second was less than 720p.
Looks like the only thing you can do is pull the video feed, check that to see if a high-res still has been generated and up-scale the smaller one yourself if not.
All¹ YouTube stills are presented in the 4:3 aspect ratio, so will always have black bars at the top and bottom if the video is 16:9. In HTML/CSS, this is easily combated by setting the image as the background of a div and sizing the div to the correct aspect.
¹ Except the mqdefault.jpg stills, which are all in 16:9 aspect (320x180)