Video preview image

I’m making a slider with a video in it and I would like it to show as a lightbox – and it’s doing that perfectly. However, I would like to have a different picture than the YouTube-chosen picture as the image on which to click to turn the video on. Is that possible?

It is only up as a test right now, here: http://cohrgroup.com/?p=423

http://wordpress.org/plugins/simple-html-slider/