Image Parts

Question

Hi, I have noticed many programs with images where it appears to be a whole image when you copy and paste, but you can individually click parts of the image and its highlighted. A good example of this would be a program like PSPICE, where you have a image resistor but you can individually click the pins of the right and left where the wires are to be connected. I don't need a concrete reply, but just some IDEAS or Platforms on which I can produce such an effect. Thanks Arindam Biswas