are you serious? we'll I'm thinking that if you're gonna ask that, then I'm going to assume that you know nothing about it. okay here goes.
1) First upload you're picture to a free hosting server, for a full list, check out this forum
http://www.createblog.com/forums/index.php?showtopic=14636 (I really like photobucket.com)
2) Get the URL to the image that you want to post
3) paste the URL into the following code, BETWEEN the quotation marks
If you still cant figure it out, I'll be sooo friggen pissed because its web design 101 right there.