学步园

using System;
using System.IO;
using System.Drawing;
using System.Text.RegularExpressions;
using System.Drawing.Imaging;

class Mytest
{
    static void Main()
    {
        string strPath = @"C:bmp";
        DirectoryInfo path = new DirectoryInfo(strPath);
        FileInfo[] files = path.GetFiles("*.bmp", SearchOption.AllDirectories);
        foreach (FileInfo item in files)
        {
            Image img = Image.FromFile(item.FullName);
            string strNewFileName = Regex.Replace(item.FullName, @".bmp$", ".jpg", RegexOptions.IgnoreCase);
            img.Save(strNewFileName, ImageFormat.Jpeg);
            img.Dispose();
        }

    }
}