Image/J, the AppletImage/J should shortly be running in a separate "Image/J" window. Note that this version requires Java 1.1 and that with slow network connections it can take 20-30 seconds to load. Quit Image/J by clicking on the "Image/J" window's close button.
Open the example images using Image/J's File/Open menu. Each image is displayed in a separate window. Not that the Open..., Import... and Save As... commands cannot be used when Image/J is running as an applet unless you use Internet Explorer 4 (both Mac and PC) with a "Trusted sites zone" that includes "http://rsbweb.nih.gov" or Sun's Hot Java browser with the unsigned applet security set to "Medium".
Run Image/J's built-in image processing benchmark (Plug-Ins menu) on the "Lena" image to test the speed of your Java virtual machine.