if you look in the menu icones on top of where you type your text there is one that look like a picture frame click on it and upload your picture it gona automaticaly attach the pic to your post.

you can use a third party image server like photobuket, flikr,picassa just to name a fiew and link it from there using code like this one replace parent with [ and ] i hade to replace as the code did not work proprely for unknown reason
Code:
 (IMG)http://i50.photobucket.com/albums/f343/poil27/assemblage1.jpg(/IMG)
the result will look like this