将图片压缩成大小格式小的图片

将对图片的操作单独写一个内，代码如下：

  1 public class DoPic
  2     {
  3
  4         /// <summary>
  5         /// 将图片转成二进制流
  6         /// </summary>
  7         /// <param name="path"></param>
  8         /// <returns></returns>
  9         public static byte[] SaveImage(String path)
 10         {
 11             FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read); //将图片以文件流的形式进行保存
 12             BinaryReader br = new BinaryReader(fs);
 13             byte[] imgBytesIn = br.ReadBytes((int)fs.Length); //将流读入到字节数组中
 14             return imgBytesIn;
 15         }
 16
 17
 18         /// <summary>
 19         /// 现实二进制流代表的图片
 20         /// </summary>
 21         /// <param name="imgBytesIn"></param>
 22         public static void ShowImgByByte(byte[] imgBytesIn, string filePathIncludeName)
 23         {
 24             MemoryStream ms = new MemoryStream(imgBytesIn);
 25
 26             Bitmap bmp = new Bitmap(ms);
 27             bmp.Save(filePathIncludeName, ImageFormat.Bmp);
 28             ms.Close();
 29         }
 30
 31
 32
 33
 34
 35         /// <summary>
 36         /// 图像缩略图处理，无损压缩图片
 37         /// </summary>
 38         /// <param name="bytes">图像源数据</param>
 39         /// <param name="compression">压缩质量 1-100</param>
 40         /// <param name="thumbWidth">缩略图的宽</param>
 41         /// <param name="thumbHeight">缩略图的高</param>
 42         /// <returns></returns>
 43         public static byte[] ConvertToThumbnail(byte[] bytes, int compression = 100, int thumbWidth = 0, int thumbHeight = 0)
 44         {
 45             byte[] bs = null;
 46
 47             try
 48             {
 49                 if (bytes != null)
 50                 {
 51                     using (MemoryStream ms = new MemoryStream(bytes))
 52                     {
 53                         using (Bitmap srcimg = new Bitmap(ms))
 54                         {
 55                             if (thumbWidth == 0 && thumbHeight == 0)
 56                             {
 57                                 thumbWidth = srcimg.Width;
 58                                 thumbHeight = srcimg.Height;
 59                             }
 60                             using (Bitmap dstimg = new Bitmap(thumbWidth, thumbHeight))//图片压缩质量
 61                             {
 62                                 //从Bitmap创建一个System.Drawing.Graphics对象，用来绘制高质量的缩小图。
 63                                 using (Graphics gr = Graphics.FromImage(dstimg))
 64                                 {
 65                                     //把原始图像绘制成上面所设置宽高的缩小图
 66                                     Rectangle rectDestination = new Rectangle(0, 0, thumbWidth, thumbHeight);
 67                                     gr.Clear(Color.WhiteSmoke);
 68                                     gr.CompositingQuality = CompositingQuality.HighQuality;
 69                                     gr.SmoothingMode = SmoothingMode.HighQuality;
 70                                     gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
 71                                     gr.DrawImage(srcimg, rectDestination, 0, 0, srcimg.Width, srcimg.Height, GraphicsUnit.Pixel);
 72
 73                                     EncoderParameters ep = new EncoderParameters(1);
 74                                     ep.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, compression);//设置压缩的比例1-100
 75                                     ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();
 76                                     ImageCodecInfo jpegICIinfo = arrayICI.FirstOrDefault(t => t.FormatID == System.Drawing.Imaging.ImageFormat.Png.Guid);
 77                                     using (MemoryStream dstms = new MemoryStream())
 78                                     {
 79                                         if (jpegICIinfo != null)
 80                                         {
 81                                             dstimg.Save(dstms, jpegICIinfo, ep);
 82                                         }
 83                                         else
 84                                         {
 85                                             dstimg.Save(dstms, System.Drawing.Imaging.ImageFormat.Png);//保存到内存里
 86                                         }
 87                                         bs = new Byte[dstms.Length];
 88                                         dstms.Position = 0;
 89                                         dstms.Read(bs, 0, bs.Length);
 90                                     }
 91                                 }
 92                             }
 93                         }
 94                     }
 95                 }
 96             }
 97             catch (Exception ex)
 98             {
 99                 //LogManager.DefaultLogger.Error(LogConvert.ParseWebEx(ex), string.Concat("ConvertToThumbnail error.", thumbWidth, " ", thumbHeight));
100             }
101             return bs;
102         }
103
104
105     }

然后调用：

1 byte[] bys = DoPic.SaveImage(System.AppDomain.CurrentDomain.BaseDirectory + "timg.png");    //得到图片的Byte数组数据
2
3
4 byte[] newPic = DoPic.ConvertToThumbnail(bys, 1, 30, 30);     //将图片进行压缩
5
6
7 DoPic.ShowImgByByte(newPic, "E:\\a.png");          //重新将新的图片保存

原文地址：https://www.cnblogs.com/Johnfx-home/p/11245557.html