How do I extract the RGB values​​?

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C#

Value does not come out right.

Bitmap b = (Bitmap)pictureBox2.Image;
if (e.X >= 0 && e.X <= b.Width && e.Y >= 0 && e.Y <= b.Height)
{
   Color c = b.GetPixel(e.X, e.Y);
   mouseCOL.Text = "R : " + c.R.ToString() + " G : " + c.G.ToString()
                 + " B : " + c.B.ToString();
   pictureBox3.BackColor = Color.FromArgb(c.R, c.B, c.G);
}

Real differs from the value

[Updated]

Bitmap b = (Bitmap)pictureBox2.Image;
if (e.X >= 0 && e.X <= b.Width && e.Y >= 0 && e.Y <= b.Height)
{
Color c = b.GetPixel(e.X, e.Y);
mouseCOL.Text = "R : " + c.R.ToString() + " G : " + c.G.ToString()
+ " B : " + c.B.ToString();
pictureBox3.BackColor = Color.FromArgb(c.R, c.B, c.G);
}

Appears a different color
pictureBox3 A different color seems to