You can post a pic in your message either by
1. click on the image icon in the menu that is displayed above when you post a new thread or post a new reply. The image icon will pop up an input bar. copy the online location of your pic into this bar and hit ok. the online location that you copy into the input bar should look something like this for example:
http://www.photobucket.com/mypic.jpg
OR
2. type your message and when you want to toss in an image, just put [img] before the address of the pic and [/img] right after the address of the pic.
Lets see some pics, do you guys have a PS3 or what?
