Copied this from technical corner, hope it helps. A lot of people have used photobucket instead of image shack.
To post a piccie already saved
Open
www.imageshack.us
Select browse
Double click on the piccie you wish to post
Make sure the options box is set to 640 x 480 and make sure the resize image box is checked
Click Host it
Copy and Paste the box that says Hotlink for forums(1)