[vtkusers] vtkImageStencilData to vtkImageData

[Luis Cordova]

I am getting a runtime error of "type vtkImageStencilData, but a
vtkImageData is required."

I was before needing to convert from PolyData to ImageData, then I use
vtkPolyDataToImageStencil, but now this error from Stencil to Image.

Anyone hints?

Thanks,