Getting Started:

Step 1: Place a FileUpload control, a Button on the Web Form.

Step 2: The user will first upload the file using FileUpload control and will then click the save button. Therefore generate the click event for the button.

Step 3: Onclick event in the code behind write the following code:

    Bitmap image = ResizeImage(flpBrowseUserImage.PostedFile.InputStream, 120, 80);

                string filename = flpBrowseUserImage.FileName.ToString();
                string extension = Path.GetExtension(filename);
                filename = filename.Replace(extension, DateTime.Now.ToString("yyyyMMddHHmmss"));
                filename = filename + extension;
                filename = filename.Replace(' ', '_').ToString();
                image.Save(Server.MapPath("~/Profile_Images/" + filename), ImageFormat.Jpeg);

   In this code block we have called a method ResizeImage()(Actually responcible for resizing the image) which I have discussed in next step.This method returns the Bitmap image after resizing it as per the passed width and height which is then saved to a location after making some changes to its name (as per the requirement).

Note: Take the reference of Dll "System.Drawing.Imaging"

Step 4: As you can see that we are using ResizeImage() method, so make a method for it as follows:

private Bitmap ResizeImage(Stream streamImage, int maxWidth, int maxHeight)
        {
            Bitmap originalImage = new Bitmap(streamImage);
            int newWidth = maxWidth;
            int newHeight = maxHeight;
            return new Bitmap(originalImage, newWidth, newHeight);
        }

   This method takes the input image stream, width and height and will return the bitmap image after resizing it.