Adding onto Jango's post above, Imgur.com is an excellent source for generating a new URL code for your image. (Sadly, the forums do not allow you to upload pictures directly from your computer to your posts.) To upload to Imgur, upload the picture from their New Post button on their homepage, move your cursor over the image and select the down arrow, then click "Get share links," and copy the BBCode it gives you; you can paste that directly onto the forum here. c:
The code for your image should look something like this:
[img]URLHERE[/img]