The default image is set to perspective. To choose between perspective and orthographic just click on either button. A status message will inform you that the image has been set to perspective or orthographic. You must fill in the x, y, z and deg values (radians) boxes and select a tranformation in the bottom bar - rotate, translate, scale or skew before clicking on the draw image button. You do not not need to select orthographic or perspective everytime you want to draw and image.
The transformations in this applet are not additive; that is, each time you choose a new tranformation, e.g. scale it will perform that tranform on a fresh copy of the image, so repeatedly hitting the scale button followed by "draw image" button without changing the x,y,z values will not make the cube shrink smaller each time.Since this applet is built on top of the Test Matrix class given, you can also click and drag the mouse across the applet in order to rotate the image. Depending on the machine, the tranformation time can be either fast or slow, so it might take a couple of seconds for the tranformation to complete.