NPOI 导出Excel图片 （网络）

https://www.cnblogs.com/peasana/p/5242420.html

导出网络图片，需要将网络图片下载到本地或者内存流中，建议下载的时候使用缩略图；

高清图片效率慢；

        Uri uri = new Uri(imgPath); //imgPath :网络图片地址

        WebRequest webRequest = WebRequest.Create(uri);

        using (WebResponse webResponse = webRequest.GetResponse())

        {

            Bitmap bitmap = new Bitmap(webResponse.GetResponseStream());

            using (MemoryStream ms = new MemoryStream())

            {

                bitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

                byte[] bytes = ms.ToArray();

                int pictureIdx = workbook.AddPicture(bytes, NPOI.SS.UserModel.PictureType.PNG);  //添加图片

                HSSFPatriarch patriarch = (HSSFPatriarch)sheet.CreateDrawingPatriarch();

                HSSFClientAnchor anchor = new HSSFClientAnchor(0, 0, 0, 240, col, row, col + 1, row + 1);

                //图片位置，图片左上角为（col, row）

                HSSFPicture pict = (HSSFPicture)patriarch.CreatePicture(anchor, pictureIdx);

                pict.Resize(); //用图片原始大小来显示

            }

        }