JW-Player use video thumbnail as featured image

If I upload external media (in particular a Youtube video) for use with the jw-player wordpress plugin... how do i use the thumbnail as my featured image ... so i can show thumbs in say the excerpts that link to the开发者_运维知识库 post where the full video is available.

the jw-player plugin seems to save the youtube screenshot as meta data, but the meta data is associated with the attachment page and not w/ the post i am adding to my blog.

If that is the case, you can use <?php wp_get_attachment_metadata( $post_id, $unfiltered ) ?>. You'll need to look through the returned array to find that image and display it.

http://codex.wordpress.org/Function_Reference/wp_get_attachment_metadata