How to get a YouTube thumbnail from a YouTube iframe?

Question

For instance I have a blog post that has the following iframe.

<iframe width="420" height="315" src="//www.youtube.com/embed/1sIWez9HAbA" frameborder="0" allowfullscreen></iframe>

How can I extract the thumbnail from this iframe?

Answer 1

YouTube thumbnails

YouTube thumbnails can be found in this standard path:

http://img.youtube.com/vi/[video-id]/[thumbnail-number].jpg

• [video-id] is the YouTube video ID, e.g. 1sIWez9HAbA.
• [thumbnail-number] is the number of the thumbnail of the 4 each video usually has, e.g. 0.

Getting the thumbnail from an iframe

So, based on the iframe's src attribute you may construct the URL of the thumbnail directly.

For example, using jQuery:

var iframe           = $('iframe:first');
var iframe_src       = iframe.attr('src');
var youtube_video_id = iframe_src.match(/youtube\.com.*(\?v=|\/embed\/)(.{11})/).pop();

if (youtube_video_id.length == 11) {
    var video_thumbnail = $('<img src="//img.youtube.com/vi/'+youtube_video_id+'/0.jpg">');
    $(body).append(video_thumbnail);
}

Note this example checks the URL of the iframe for a valid YouTube video ID and assumes it to be 11 characters long, which is the de facto standard.

See jsFiddle Demo