upload your pictures to phtobucket or tiny pics.
If you use photobucket, and you have to do is click the bottom of the share options to copy it and paste it here.
Or for any picture on the web, including those you've uploaded from your computer, right click and copy image location, then either paste the link between
or select the little icon of the tree (insert image) at the top of the editor box here, select from url, unclick the retrieve and reference box, paste your link and select ok/
with any of those methods you should end up with
which is what you need to post a picture
(i haven't had nearly enough coffee yet- so i can only hope that was at least a tiny bit coherent)