In order to post your picture on the board, you need to have your .jpeg image somewhere out there on a web server where it can be "pulled" by the forum software whenever it needs to display your picture.
Most internet accounts allow the user a small slice of "webspace" where they can store things (like a personal or family web site). If you can figure out how to place an image there, great. The size is 80 x 80 pixels. If you can't figure that out, you can always send me a picture and I'll put it up on the gunks web server.