You need the photo to be hosted somewhere and then stick the full URL between the [ img][ /img] tags. i.e. "[ img]http://"
www.picofcar.co.uk"[ /img]"
You dont need the speech marks and there's no space between the '[ and the i or the /, it's just that it tries to show a pick if you dont do it that way.
If there's a car for sale and it has pics of it, just pretend to reply by doing a 'quote' on that thread and it will show you an example of how it's done. Any of this make any sense