One way is to post the IMG code for the picture.
[IMG]http://i33.tinypic.com/2nk5e21.jpg[/IMG]
First I put [IMG], than i put:
i33.tinypic.com/2nk5e21.jpg, and last I put: [/IMG]
-----
To find the code, save the picture, than upload the code from a website such as tinypic.com
There will be a box that says Browse, click it and choose your picture. Click where it says "Upload Now". Then copy and paste the IMG code that comes up on the right side of the screen.