import vtk.vtkImageViewer2;
import vtk.vtkPNGReader;
import vtk.vtkNativeLibrary;
import vtk.vtkRenderWindowInteractor;

public class PNGReader 
{
  //-----------------------------------------------------------------
  // Load VTK library and print which library was not properly loaded
  static 
  {
    if (!vtkNativeLibrary.LoadAllNativeLibraries()) 
    {
      for (vtkNativeLibrary lib : vtkNativeLibrary.values()) 
      {
        if (!lib.IsLoaded()) 
        {
          System.out.println(lib.GetLibraryName() + " not loaded");
        }
      }
    }
    vtkNativeLibrary.DisableOutputWindow(null);
  }
  // -----------------------------------------------------------------

  public static void main(String args[]) 
  {
    //parse command line arguments
    if (args.length != 1) {
      System.err.println("Usage: java -classpath ... Filename(.png) e.g Test.png");
      return;
    }
    //  Read the image
    vtkPNGReader reader = new vtkPNGReader();
    reader.SetFileName(args[0]);
    
    //  Visualize
    vtkImageViewer2 imageViewer = new vtkImageViewer2();
    imageViewer.SetInputConnection(reader.GetOutputPort());
    vtkRenderWindowInteractor renderWindowInteractor = new vtkRenderWindowInteractor();
    imageViewer.SetupInteractor(renderWindowInteractor);
    imageViewer.Render();
    imageViewer.GetRenderer().ResetCamera();
    imageViewer.Render();

    renderWindowInteractor.Start();
  }
}

import vtk.vtkImageViewer2;
import vtk.vtkPNGReader;
import vtk.vtkNativeLibrary;
import vtk.vtkRenderWindowInteractor;

public class PNGReader 
{
  //-----------------------------------------------------------------
  // Load VTK library and print which library was not properly loaded
  static 
  {
    if (!vtkNativeLibrary.LoadAllNativeLibraries()) 
    {
      for (vtkNativeLibrary lib : vtkNativeLibrary.values()) 
      {
        if (!lib.IsLoaded()) 
        {
          System.out.println(lib.GetLibraryName() + " not loaded");
        }
      }
    }
    vtkNativeLibrary.DisableOutputWindow(null);
  }
  // -----------------------------------------------------------------

  public static void main(String args[]) 
  {
    //parse command line arguments
    if (args.length != 1) {
      System.err.println("Usage: java -classpath ... Filename(.png) e.g Gourds.png");
      return;
    }
    //  Read the image
    vtkPNGReader reader = new vtkPNGReader();
    reader.SetFileName(args[0]);
    
    //  Visualize
    vtkImageViewer2 imageViewer = new vtkImageViewer2();
    imageViewer.SetInputConnection(reader.GetOutputPort());
    vtkRenderWindowInteractor renderWindowInteractor = new vtkRenderWindowInteractor();
    imageViewer.SetupInteractor(renderWindowInteractor);
    imageViewer.Render();
    imageViewer.GetRenderer().ResetCamera();
    imageViewer.Render();

    renderWindowInteractor.Start();
  }
}

Update PNGReader.java