Go here [url=www.imageshack.com]Click[/url]
Browse
Select pic
Upload
Take url from very top of results page ie: Highlight then copy.
Click on this icon in reply
Eventhough it doesn't work for me here it might for you. I have to type them in. That'd be img in brackets then /img in brackets. If I type them in to show you they won't show. A bracket is this: [ then this ] around img then /img.
Paste url between Image brackets.