http://www.photobucket.com
Set up an account with photobucket. Upload your pics directly onto Photobucket then copy the URL link as stated under the picture you want to post here. Then paste the URL in between [img]and[/img] (with no spaces).
e.g.
(minus the space between jpeg and [/img] )
Preview your message before posting it. All formatting tricks should be working when you preview your message, so if the link is working the picture should be displayed then.