Web Forms :: Resize Large Number Of Images In A Folder In C# Windows Application

How to resize large number of images in a folder  in c# windows application. I am using following code to resize images of my folders. If images are less than 1600 ( in number) then no problem but if images are more than 1600 then i am getting error. My code is given below:-

public static Image ResizeImage(string file, int width, int height, bool onlyResizeIfWider) {
using (Image image = Image.FromFile(file)) {
// Prevent using images internal thumbnail
image.RotateFlip(RotateFlipType.Rotate180FlipNone);
image.RotateFlip(RotateFlipType.Rotate180FlipNone);

[Code] ....

Thumbnail creation in ASP.Net: System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI