在dotnet中生成jpg缩略图

using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

public static void GenerateThumbnail(string inputPath, string outputPath, int width, int height)
{
    using (Image originalImage = Image.FromFile(inputPath))
    {
        int sourceWidth = originalImage.Width;
        int sourceHeight = originalImage.Height;

        // 计算缩略图的宽度和高度
        int thumbnailWidth = width;
        int thumbnailHeight = height;

        // 如果原始图像的宽度和高度都大于缩略图的宽度和高度，则按比例缩放
        if (sourceWidth > width && sourceHeight > height)
        {
            double widthRatio = (double)width / sourceWidth;
            double heightRatio = (double)height / sourceHeight;
            double scaleRatio = Math.Min(widthRatio, heightRatio);

            thumbnailWidth = (int)(sourceWidth * scaleRatio);
            thumbnailHeight = (int)(sourceHeight * scaleRatio);
        }

        // 创建缩略图
        using (Bitmap thumbnailImage = new Bitmap(thumbnailWidth, thumbnailHeight))
        {
            using (Graphics graphics = Graphics.FromImage(thumbnailImage))
            {
                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                graphics.SmoothingMode = SmoothingMode.HighQuality;
                graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
                graphics.CompositingQuality = CompositingQuality.HighQuality;

                graphics.DrawImage(originalImage, new Rectangle(0, 0, thumbnailWidth, thumbnailHeight));
            }

            // 保存缩略图为JPG格式
            thumbnailImage.Save(outputPath, ImageFormat.Jpeg);
        }
    }
}