title: How to use vtkPNGWriter with interactor?
body: <p>I am new to VTK and using python bindings. I am trying to render some objects as images. I am using vtkPNGWriter to save the rendered image. I want to attach the vtkPNGWriter to the interactor so that it saves the rendered images after every time I change the object pose using the interactor. Could someone please help me with this task?</p>