You could try to save the image using this approach
SaveFileDialog dialog=new SaveFileDialog();
if (dialog.ShowDialog()==DialogResult.OK)
{
int width = Convert.ToInt32(drawImage.Width);
int height = Convert.ToInt32(drawImage.Height);
using(Bitmap bmp = new Bitmap(width, height))
{
drawImage.DrawToBitmap(bmp, new Rectangle(0, 0, width, height));
bmp.Save(dialog.FileName, ImageFormat.Jpeg);
}
}