抛出异常时，保存在文件服务器的形象
您好，
当我试图保存在服务器，它抛出下面的错误形象。
A generic error occurred in GDI+.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI+.
Source Error:
Line 166: if (objFileUpload.impersonateValidUser())
Line 167: {
Line 168: ImgThnail.Save(Path.Combine(objFileServerImpersonation.FileServerPath(), ThumbnailPath), Img.RawFormat);
Line 169:ImgThnail.Dispose();
我使用Impersonate方法来验证用户凭据，检查从服务器获取权限。