/// <summary>
/// 图片压缩
/// </summary>
/// <param name="imagePath">图片文件路径</param>
/// <param name="targetFolder">保存文件夹</param>
/// <param name="quality">压缩质量</param>
/// <param name="fileSuffix">压缩后的文件名后缀（防止直接覆盖原文件）</param>
public static void CompressionImage(string imagePath, string targetFolder, long quality, string fileSuffix = "Demo")
{if (!System.IO.File.Exists(imagePath)){throw new FileNotFoundException();}if (!Directory.Exists(targetFolder)){Directory.CreateDirectory(targetFolder);}var fileInfo = new FileInfo(imagePath);var fileName = fileInfo.Name.Replace(fileInfo.Extension, "");var fileFullName = Path.Combine($"{targetFolder}", $"{fileName}_{fileSuffix}{fileInfo.Extension}");var imageByte = CompressionImage(imagePath, quality);var ms = new MemoryStream(imageByte);var image = Image.FromStream(ms);image.Save(fileFullName);ms.Close();ms.Dispose();image.Dispose();
}/// <summary>
/// 设置图片质量
/// </summary>
/// <param name="imagePath"></param>
/// <param name="quality">范围0~100，越大质量越高</param>
/// <returns></returns>
private static byte[] CompressionImage(string imagePath, long quality)
{using (var fileStream = new FileStream(imagePath, FileMode.Open)){using (var img = Image.FromStream(fileStream)){using (var bitmap = new Bitmap(img)){ImageCodecInfo codecInfo = GetEncoder(img.RawFormat);var myEncoder = System.Drawing.Imaging.Encoder.Quality;var myEncoderParameters = new EncoderParameters(1);var myEncoderParameter = new EncoderParameter(myEncoder, quality);myEncoderParameters.Param[0] = myEncoderParameter;using (var ms = new MemoryStream()){bitmap.Save(ms, codecInfo, myEncoderParameters);myEncoderParameters.Dispose();myEncoderParameter.Dispose();return ms.ToArray();}}}}
}/// <summary>
/// Guid
/// </summary>
/// <param name="format"></param>
/// <returns></returns>
private static ImageCodecInfo GetEncoder(ImageFormat format)
{var codecs = ImageCodecInfo.GetImageDecoders();return codecs.FirstOrDefault(codec => codec.FormatID == format.Guid);
}

调用方法：

CompressionImage("C:\\Users\\admin\\Desktop\\画图\\1.jpg", "C:\\Users\\admin\\Desktop\\画图\\Demo", 50, "Demo");