Call the following function which takes one bitmap image and it returns one image.

public Bitmap Generate_negative_image(Bitmap sourceimage)

{

Color c;

for (int i = 0; i < sourceimage.Width; i++)

{

for (int j = 0; j < sourceimage.Height; j++)

{

c = sourceimage.GetPixel(i,j);

c = Color.FromArgb(255 - c.R, 255 - c.G, 255 - c.B);

sourceimage.SetPixel(i, j, c);

}

}

return sourceimage;

}

How to call.:

protected void button1_Click_1(object sender, EventArgs e)

{

pictureBox1.Image = Generate_negative_image((Bitmap)pictureBox1.Image);

}

Here I am taking one image from picturebox , then it is type casted in bitmap and then passed to the function .

And it returned image is assigned to picturebox.