I have a photobucket account (www.photobucket.com)
I upload my pictures there, and it provides me with the various codes: E-mail and IM link, Direct link, HTML code and IMG code.
The one used on this courm is the IMG code. Simply copy that and paste it into the message.
This is what an IMG code looks like:
[IMG*]http/i1219.photobucket.com/albums/dd437/RoseSky22/oyvey2012.jpg[/IMG*] Just remove the *'s and it will turn into your picture
This is simply the way I do it, there are other ways to do it as well
p.s: aren't my Panda Cory's so lovely?