When you post your message, you should see a line at the bottom of the window that says "Click here to upload!". Click on that, then click on one of the "Browse" buttons, browse to your image file, click OK, wait for the "File Uploaded Successfully." message, click OK, then send your message. You can also check the "Embed picture in post" checkbox if you want. I uploaded this screenshot of what it looks like. Hope this helps. Also, your file must be smaller than 500k.
get a photobucket account at photobucket.com upload your picture on there it right click the direct link url and the last button on the right at the bottom of this box is add image paste that url and away ya go