I’ve updated the site today so that if you click the thumbnail image for a video the download starts. Previously the preview images were shown when you did this.
Let me know if you experience any problems related to this.
It’s supposed to work like this: if you hover the mouse pointer over the image you should see a download icon. When you click it, it should say “loading…” and the download should start. Then the “loading…” message should disappear after a few seconds.