C# Bitmap/png转成jpg格式，压缩图片

public static ImageCodecInfo GetEncoder(ImageFormat format)

        {

            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();

            foreach (ImageCodecInfo codec in codecs)

            {

                if (codec.FormatID == format.Guid)

                    return codec;

            }

            return null;

        }

Bitmap im = 这里是原图片

                //转成jpg

                var eps = new EncoderParameters();

                var ep = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 85L);

                eps.Param[] = ep;

                var jpsEncodeer = GetEncoder(ImageFormat.Jpeg);

                //保存图片

                imgurl = @"/Content/Upload/" + guid + extension;

                im.Save(path + imgurl,jpsEncodeer,eps);

                //释放资源

                im.Dispose();

                ep.Dispose();

                eps.Dispose();