asp.net 图片压缩后背景变黑色问题

[keatkeat1987]

从网上抓来一些代码，效果不错，可是压缩后图片被来的透明背景却变黑色的了 。
高手帮帮忙丫～～ 万分感激 ！

private System.Drawing.Imaging.ImageCodecInfo GetEncoderInfo(string mimeType)
{
    System.Drawing.Imaging.ImageCodecInfo result = null;
    
    System.Drawing.Imaging.ImageCodecInfo[] encoders =
        System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders();
    for (int i = 0; i < encoders.Length; i++)
    {
        if (encoders[i].MimeType == mimeType)
        {
            result = encoders[i];
            break;
        }
    }
    return result;
}

System.Drawing.Bitmap img = new System.Drawing.Bitmap("C:\\source.jpg"); 
//System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(img);


System.Drawing.Imaging.ImageCodecInfo encoder = GetEncoderInfo("image/jpeg");
if (encoder != null)
{
    System.Drawing.Imaging.EncoderParameters encoderParams =
       new System.Drawing.Imaging.EncoderParameters(1); 
   
    encoderParams.Param[0] =
        new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)60);
    
    img.Save("C:\\destination.jpg", encoder, encoderParams);
    
    encoderParams.Dispose();
}


//graphics.Dispose();
img.Dispose();

[YiYanXiYin]

jpg不支持透明的,你换gif或者png试试