You can do this by either pasting the image address into the post window and adding [img] at the beginning and [/img] at the end see below:

'[img]http://lh4.ggpht.com/_mKDfkSOVHgQ/Sq5L3lMTVnI/AAAAAAAADJE/aqvgN5LWv9g/s640/IMG00070-20090912-1833.jpg[/img]

and this is what will appear:

size]

JHAP
~~~~~~~~~~
"My mind is a raging torrent, flooded with rivulets of thought cascading into a waterfall of creative alternatives."
...Hedley Lamarr (that's Hedley not Hedy)