If you have Java installed and activated with your web browser, a frame should open up with the jiuawt demo program. The JAR file is downloaded first. It is about 500 KB large, so if you are on a slow network connection this may take some time.
You cannot load or save image files from the file system in an applet which has not been signed. To give you something to play with, pick the menu item image1.jpg in the file menu.