I take a screenshot of the screen area, then search for a match using the template.
An error appears on the line.

Image<Bgr, Byte> source = Emgu.CV.BitmapExtension.ToImage<Bgr, Byte>(bitmap);

System.ArgumentException: “Parameter is not valid.”

    using System.Runtime.InteropServices;
    using System.Windows;
    using System.Windows.Forms;
    
    
    using Emgu.CV;
    using Emgu.CV.Structure;
    using Emgu.CV.CvEnum;
    using Emgu.CV.Util;
        
    private void btnStart_Click(object sender, EventArgs e)
        {
            RECT rect;
            rect.left = 0;
            rect.top = 0;
            rect.right = 1200;
            rect.bottom = 800;
            Rectangle bounds = new Rectangle(rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top);
            var bitmap = new Bitmap(bounds.Width, bounds.Height);
            using (bitmap)
            {
                using (var g = Graphics.FromImage(bitmap))
                {
                    g.CopyFromScreen(new Point(bounds.Left, bounds.Top), Point.Empty, bounds.Size);
                }
            }
    
            //----** ERROR**
            
            Image<Bgr, Byte> source = Emgu.CV.BitmapExtension.ToImage<Bgr, Byte>(bitmap);
            //  and this option doesn't work
            // Image<Bgr, Byte> source = bitmap.ToImage<Bgr, Byte>();
    
    
            Image<Bgr, byte> template = new Image<Bgr, byte>("scr-over/temple.bmp");
            Image<Bgr, byte> imageToShow = source.Copy();
            using (Image<Gray, float> result = source.MatchTemplate(template, Emgu.CV.CvEnum.TemplateMatchingType.CcoeffNormed))
            {
                double[] minValues, maxValues;
                Point[] minLocations, maxLocations;
                result.MinMax(out minValues, out maxValues, out minLocations, out maxLocations);
                if (maxValues[0] > 0.9)
                {
                    Rectangle match = new Rectangle(maxLocations[0], template.Size);
                    imageToShow.Draw(match, new Bgr(Color.Red), 1);
                    pictureBox1.Image = imageToShow.ToBitmap();
                }
            }
            imageToShow.Save("scr-over/result.bmp");
            
        }