Button customizations
You can use either the button set included with the system, r_led.gif, y_led.gif, g_led.gif, and n_led.gif, or any other set of images as long as the images are .GIF or .JPEG.
The system includes an example button set with a base name of smile.gif. g_smile.gif is a happy face, y_smile.gif is a neutral face, r_smile.gif is a frowning face, and n_smile.gif is a blank face. You can use this button set to learn about the img parameter.