using System.IO;

using System.Drawing.Imaging;

 

public class imgConvert

{

    private void BMPToJPG(string bmpFileName,string jpgFileName)

    {

         

       System.Drawing.Image img;

       img=ReturnPhoto(bmpFileName);

   

       img.Save(jpgFileName,ImageFormat.Jpeg);

    }

 

    private Image ReturnPhoto(string bmpFileName)

    {

       System.IO.FileStream stream ;

       stream=File.OpenRead(bmpFileName);

       Bitmap bmp = new Bitmap(stream);

       System.Drawing.Image image = bmp;//得到原图

       //创建指定大小的图

       System.Drawing.Image newImage = image.GetThumbnailImage(bmp.Width, bmp.Height, null, new IntPtr());

       Graphics g=Graphics.FromImage(newImage);

       g.DrawImage(newImage,0,0, newImage.Width, newImage.Height); //将原图画到指定的图上

       g.Dispose();

       stream.Close();

       return newImage;

    }

}