图片转换，把bmp图片转换为jpg图片

图片转换，把bmp图片转换为jpg图片，用.net的类库很简单哦。

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;
         }
 }