Right click on the image you wish to post, then go down to where you see 'Properties' - left click on that - then copy and paste the url of the image and put the vb image tags round it like so:-
[*img]http://www.cheesyquizbanner/cheesy.jpg[*/img]
Just remember to take out the * or the image won't show up.🙂
It sounds like the first time you did it you didn't right click.🙂
Hope that helps - alternatively if they provide you with the html code for the banner, then copy and paste the url of the image out of it, and change the '<img src=' coding for the [*img] & [/*img] tags. Just check and make sure that you can actually link to the image because some of these quiz sites ask you to save the pic elsewhere instead of linking to their sites. 😉