It has to be off the internet.

Let's say you upload the image to photobucket.com and get an address like http://www.photobucket.com/images/screenshot.png (not going to work). You then use an [IMG] tag and stick the address in there, like this: [IMG]http://www.photobucket.com/images/screenshot.png[/IMG]

You can also upload your images to digiex.net here. Just copy the location of the image and repeat the steps.