If I take the code you copied from Stack Overflow:
http://stackoverflow.com/questions/30954503/how-to-crop-a-polygonal-area-from-an-image-in-a-winform-picturebox[
^]
And tweak it slightly to fit a test image:
Point[] points = new Point[] { new Point(60, 10), new Point(100, 60), new Point(60, 110), new Point(10, 60), new Point(60, 10) };
GraphicsPath gp = new GraphicsPath();
gp.AddPolygon(points.ToArray());
Bitmap bmp1 = new Bitmap(120, 120);
using (Bitmap bmp0 = (Bitmap)Bitmap.FromFile(imagePath))
{
using (Graphics G = Graphics.FromImage(bmp1))
{
G.Clip = new System.Drawing.Region(gp);
G.DrawImage(bmp0, 0, 0);
bmp1.Save(imageOutPath, ImageFormat.Jpeg);
}
}
It works fine - I get a diamond of image inside a black image.
Looking at your region, it doesn't fit inside your output image...which may explain the problem...