The og:image on that page is pointing to
www.baden-haber.de/images/2016/12/18/Tiger Sport Akademie.jpg which is the image you're seeing in the preview. There's no image in the article. JFBConnect doesn't add video tags by default, but you can easily add our SCOpenGraph easy-tag to specify the video data. For example
{SCOpenGraph video=FULL_URL_PATH_TO_VIDEO}
{SCOpenGraph video:type=video/mp4}
{SCOpenGraph video:width=400}
{SCOpenGraph video:height=400}
{SCOpenGraph image=FULL_URL_PATH_TO_IMAGE_PREVIEW}
If you need full details on these Open Graph tags, please check out the
Facebook documentation
-Melissa