you probably do quick reply right? do the go advanced one. you know how to upload a pic onto photobucket right? well do that. at the bottom of the pic on photobucket should be a code for img tags that looks like this
copy n paste that and come back here and click the little picture icon in go advanced and it will pop up with a ..pop up. anyway put the code into that and hit ok. it will put the coded image into the message but make sure you delete the extra