The easiest JavaScript way that I found to get the thumbnail, without searching for the video id is using:
//Get the video thumbnail via Ajax
$.ajax({
type:'GET',
url: 'https://vimeo.com/api/oembed.json?url=' + encodeURIComponent(url),
dataType: 'json',
success: function(data) {
console.log(data.thumbnail_url);
}
});
Note: If someone need to get the video thumbnail related to the video id he can replace the $id
with the video id and get an XML with the video details:
http://vimeo.com/api/v2/video/$id.xml
Example:
http://vimeo.com/api/v2/video/198340486.xml