我正在上载该图像的缩略图副本并将其保存在缩略图文件夹中。

我正在使用以下链接：

http://weblogs.asp.net/markmcdonnell/archive/2008/03/09/resize-image-before-
uploading-to-
server.aspx

但

newBMP.Save(directory + "tn_" + filename);

导致异常“ GDI +中发生一般错误”。

我尝试授予文件夹权限，还尝试在保存时使用新的单独bmp对象。

编辑：

    protected void ResizeAndSave(PropBannerImage objPropBannerImage)
    {
        // Create a bitmap of the content of the fileUpload control in memory
        Bitmap originalBMP = new Bitmap(fuImage.FileContent);

        // Calculate the new image dimensions
        int origWidth = originalBMP.Width;
        int origHeight = originalBMP.Height;
        int sngRatio = origWidth / origHeight;
        int thumbWidth = 100;
        int thumbHeight = thumbWidth / sngRatio;

        int bannerWidth = 100;
        int bannerHeight = bannerWidth / sngRatio;

        // Create a new bitmap which will hold the previous resized bitmap
        Bitmap thumbBMP = new Bitmap(originalBMP, thumbWidth, thumbHeight);
        Bitmap bannerBMP = new Bitmap(originalBMP, bannerWidth, bannerHeight);

        // Create a graphic based on the new bitmap
        Graphics oGraphics = Graphics.FromImage(thumbBMP);
        // Set the properties for the new graphic file
        oGraphics.SmoothingMode = SmoothingMode.AntiAlias; oGraphics.InterpolationMode = InterpolationMode.HighQualityBicubic;

        // Draw the new graphic based on the resized bitmap
        oGraphics.DrawImage(originalBMP, 0, 0, thumbWidth, thumbHeight);

        Bitmap newBitmap = new Bitmap(thumbBMP);
        thumbBMP.Dispose();
        thumbBMP = null;

        // Save the new graphic file to the server
        newBitmap.Save("~/image/thumbs/" + "t" + objPropBannerImage.ImageId, ImageFormat.Jpeg);

        oGraphics = Graphics.FromImage(bannerBMP);
        // Set the properties for the new graphic file
        oGraphics.SmoothingMode = SmoothingMode.AntiAlias; oGraphics.InterpolationMode = InterpolationMode.HighQualityBicubic;

        // Draw the new graphic based on the resized bitmap
        oGraphics.DrawImage(originalBMP, 0, 0, bannerWidth, bannerHeight);
        // Save the new graphic file to the server
        bannerBMP.Save("~/image/" + objPropBannerImage.ImageId + ".jpg");


        // Once finished with the bitmap objects, we deallocate them.
        originalBMP.Dispose();

        bannerBMP.Dispose();
        oGraphics.Dispose();
    }