I am using video field embed to create a video field that is part of an node gallery. I allow an unlimited number of fields in the widget. In a view, I add video as a field and choose the thumbnail formatter. I've tried this with both normal and teaser video modes. Everything works great except that the thumbnail is blank, and if I try to view it I just get "Error generating image." It would be good if the YouTube thumbnail was available or even if there were just a default thumb that showed a video icon.