title: getting System.Runtime.InteropServices.ExternalException!
body: <p>I am trying to paint the image and save it by using the mouse click event. I added a button to undo the last paint operation. I am performing this operation by loading the previously saved image by mouse click event. I have a code here... I'll show the part where i get the exception in comments in the code:</p>
  
  <pre><code>private void pictureBox1_MouseClick(object sender, MouseEventArgs e)
  {
      rect.Width = 0;
      rect.Height = 0;
      pictureBox1.Invalidate();
  
      pictureBox1.Image.Save(String.Format("{0}.Bmp",textBox2.Text )); //getting exception here!! 
  
      int radius = 10; //Set the number of pixel you want to use here
  
      //Calculate the numbers based on radius
      int x0 = Math.Max(e.X - (radius / 2), 0),
          y0 = Math.Max(e.Y - (radius / 2), 0),
          x1 = Math.Min(e.X + (radius / 2), pictureBox1.Width),
          y1 = Math.Min(e.Y + (radius / 2), pictureBox1.Height);
  
      Bitmap bm = pictureBox1.Image as Bitmap; //Get the bitmap (assuming it is stored that way)
      for (int ix = x0; ix &lt; x1; ix++)
      {
          for (int iy = y0; iy &lt; y1; iy++)
          {
              bm.SetPixel(ix, iy, Color.Black); //Change the pixel color, maybe should be relative to bitmap
          }
      }
      pictureBox1.Refresh(); //Force refresh
  }
  </code></pre>
  
  <p>the code under button is:</p>
  
  <pre><code>private void button2_Click(object sender, EventArgs e)
  {
      pictureBox1.Load(string.Format("{0}.Bmp",textBox2.Text));
  }
  </code></pre>
  
  <p>In my program I tried to save the image first and then painted it. When I click the button it is working &amp; loading the image, but when I again tried to paint it, there I am getting the exception. Please help where I need to change the code.</p>