okay the image must be hosted somewhere on the net so you have an URL to it
for example the URL to the image I put up is this.....
http://www.ebaumsworld.com/forumfun/negative19.jpg
if you click on that link it will open the image in a new page
but if you put [/img]
around the URL, it will link to the URL and display the image in the post you are making
does that make sense?