I'm not sure what files you downloaded but in order to cut a 3D image you'll nee to draw, one way or another, a vector around your image. It can be an oval or a square. Ir even better a vector just on the outside of you image. Once that's done, you go to the 3D finish toolpath icon and click on the 3D finish toolpath. Click on the vector that encompasses your image, set up the tool you want to use. For example a .25 ball nose, and click calculate. You should get a toolpath when it's done. Run your toolpath and you should get a 3D image. Hope this helps.
Shark HD 2.0