OK I finally figured it out. The instructions on the AVR site are incorrect. To newbs (like me) this would be a huge problem.
For anyone that couldn't figure it out the code is:{flv img="yourpicture.jpg" showstop="true"}yourvideo{/flv}
You will note that there is a space between flv and img at the beginning. The instructions show them as one word.
Hope this helps someone.