Very Simple Rss Edit

Need a change on rss output..I use this php code: http://www.phpsugar.com/pm_demo/

this script has rss like this: http://www.phpsugar.com/pm_demo/rss.php

every video has a thumbnail…but in rss no thubnail are showng..
I need show thumbnail in rss output too..so you need to add thubnails of video in rss too