Hi br... to be able to show 'images' of your vehicle in your posting... you need to use a resource like 'photobucket' or some other 'online host' that displays your personal images.
Then, you can use the actual 'url' of the link to show the image in your posting. A good example is this persons 'for sale' post:
You'll see pictures of his car in the thread... but it's because he actually has his 'images' hosted at Photobucket. Using a 'Tag' like this... put (img) before the url address and (/img) after the url address... also replace the ( ) with [ ] for your actual image url...