you click on the link to post the image to the site then a drop down box comes up.....
think I use the one that says host a image
you have to host it (which means upload your image to a host site first) eg- on another site and then find the picture on your pc and click host...
when you see the link details come up in the box you copy the link....
you then close the link box and when you see your reply screen
you then paste the link.......
it usually begins with [url] then link details / host site details here [url] from what I remember though I am tired right now and half a sleep..lol
when I have more time I will try to give better advice on this issue...
I had problems when I first started so it can be annoying till you are shown or you get the hang of it...