I have a photobucket.com account for storing pictures I have used in forums. You upload them there and each picture is given an image code. This code can just be copy and pasted into the forum. Example.
The code for this picture, that I have just copied straight from photobucket is this:
[IMGwhoop!]http://i33.photobucket.com/albums/d84/wannabemexican123/Bloomilk/redleader.jpg[/IMG]
I just added the whoop! in or it would have posted the whole image again.