i have the same problem, but changing the js did not work for me.
I’m with no other plugins active, twenty ten them and wordpress 3.7
i made a contribution to the plugin beacuase i had the same problem
https://github.com/caminantestelar/image-widget
i hope it helps
when i comment the post thumbnail in content.php, it also delted the thumbnail from the category archive…
i insert the css grunion. it solved the problem, but i cant see how to remove embed shortcodes.
i have a multisite with twenty twelve.
i guess i´ll have to stick with that
