title: Save an image in C#
body: <p>I have code that's supposed to save a picture (Bitmap) and it doesn't save it and throws an exception every time, what is the problem? </p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.ComponentModel;
  using System.Data;
  using System.Drawing;
  using System.Linq;
  using System.Text;
  using System.Threading.Tasks;
  using System.Windows.Forms;
  using System.Drawing.Imaging;
  using System.IO;
  
  namespace PicConv {
      public partial class Form1 : Form {
          Bitmap bmp;
          Bitmap bmp2;
          public Form1() {
              InitializeComponent();
          }
  
          private void button1_Click(object sender, EventArgs e) {
  
              for (int y = 0; y &lt; bmp.Height; y++) {
                  for (int x = 0; x &lt; bmp.Width; x++) {
                      Color c = bmp2.GetPixel(x, y);
                      byte r = c.R;
                      byte g = c.G;
                      byte b = c.B;
  
                      byte I = (byte)(0.3 * r + 0.59 * g + 0.11 * b);
                      Color c1 = Color.FromArgb(I, I, I);
                      bmp2.SetPixel(x, y, c1);
                  }
              }
              pictureBox2.Image = bmp2;
              pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
          }
  
          private void pictureBox1_Click(object sender, EventArgs e) {
              bmp = new Bitmap(@"C:\pic.bmp");
              pictureBox1.Image = bmp;
              pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
              bmp2 = (Bitmap)bmp.Clone();
          }
  
          private void button2_Click(object sender, EventArgs e) {
              try {
                  if (bmp2 != null) {
                      bmp2.Save(@"c:\test.bmp"); // &lt;- this throws an exception every time and won't save anything
                  }
              } catch (Exception ex) {
                  MessageBox.Show("Error: " + ex.Message);
              }
          }
      }
  }
  </code></pre>
  
  <p>I made it pop up a message box window telling me what the error is and it says "A generic error occured in GDI+".</p>