I'm new to Allvideos. It looks very powerful.

I want it use it with Youtube.

In this example:
{youtube}heu37ej3qs{/youtube}

How would I specify a thumbnail to be displayed instead of the one somewhat randomly selected by Youtube?
I'd like to create a graphic and have that displayed in the same space where the video is, and when the visitor to the website clicks on the graphic the Youtube video would play as it normally does.

How can this be done? It looks like this is being done here in a website JoomlaWorks.net mentioned is using Allvideo plugin:
www.impactwrestling.com/

Look in the above URL and see on the right where it says Video Gallery. Notice how a graphic is displayed first in the youtube video before it's played and then it proceeds normally to play the Youtube video. That's what I want to be able to do, create my own graphic to display before the user clicks on the video. Thanks!