In the second area you can put a reference to an image. This reference has to be an URL, Uniform Resource Locator, e.g.:
http://www.somewhere.edu/pictures/whatever.jpeg
Every image you see in the web is located via an URL. You can find the exact location of every image by clicking on it with your right mousebutton. A pop-up menu will appear where you can choose to copy the image location to the clipboard. Now all you have to do is paste this information into the graphics URL box when you return to the Graffiti Form. On a Macintosh you can press your mousebutton down for a longer period of time and the same pop-up menu will appear.
If you want to contribute original art, you'll have to find a place in the World Wide Web for it first. Your homepage would be a great place!
You can sign your message with any name you like, but you must leave your correct E-mail address. Optionally, you can link your signature to your place in cyberspace.