How To Resize Large Image With Good Quality Using C# Coding

Nowadays we need to store images in the cloud and then show them in many places like if create an E-commerce website then image galleries can be an effective method of communicating with the visitor. But if we upload large-size images then its increases the cost of storage and takes time to load on the browser so A nice compromise to this situation is to present images as thumbnails. This article shows how to Resize a large image with good quality.

Follow these simple steps:

Steps:

1. Select Image which you want to Resize and upload on the server.
   
2. Go to the Controller section and add the following assemblies. Create function of “ResizeImage()” in controller.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Drawing;
using Watermark;
using System.Windows.Forms;
using System.IO;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;

namespace ResizeLargeImageWithGoodQuality.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index(string imgName)
        {
            ViewBag.ImgName = imgName;
            return View();
        }

        public ActionResult UploadImageThumb(HttpPostedFileBase fileToUpload)
        {
            string myfile = ResizeImage(fileToUpload);
            return RedirectToAction("Index", new { imgName = myfile });
        }

        public string ResizeImage(HttpPostedFileBase fileToUpload)
        {
            string name = Path.GetFileNameWithoutExtension(fileToUpload.FileName);
            var ext = Path.GetExtension(fileToUpload.FileName);
            string myfile = name + ext;

            try
            {
                using (Image image = Image.FromStream(fileToUpload.InputStream, true, false))
                {

                    var path = Path.Combine(Server.MapPath("~/resizeImageStore"), myfile);
                    try
                    {
                        //Size can be change according to your requirement 
                        float thumbWidth = 270F;
                        float thumbHeight = 180F;
                        //calculate  image  size
                        if (image.Width > image.Height)
                        {
                            thumbHeight = ((float)image.Height / image.Width) * thumbWidth;
                        }
                        else
                        {
                            thumbWidth = ((float)image.Width / image.Height) * thumbHeight;
                        }

                        int actualthumbWidth = Convert.ToInt32(Math.Floor(thumbWidth));
                        int actualthumbHeight = Convert.ToInt32(Math.Floor(thumbHeight));
                        var thumbnailBitmap = new Bitmap(actualthumbWidth, actualthumbHeight);
                        var thumbnailGraph = Graphics.FromImage(thumbnailBitmap);
                        thumbnailGraph.CompositingQuality = CompositingQuality.HighQuality;
                        thumbnailGraph.SmoothingMode = SmoothingMode.HighQuality;
                        thumbnailGraph.InterpolationMode = InterpolationMode.HighQualityBicubic;
                        var imageRectangle = new Rectangle(0, 0, actualthumbWidth, actualthumbHeight);
                        thumbnailGraph.DrawImage(image, imageRectangle);
                        var ms = new MemoryStream();
                        thumbnailBitmap.Save(path, ImageFormat.Jpeg);
                        ms.Position = 0;
                        GC.Collect();
                        thumbnailGraph.Dispose();
                        thumbnailBitmap.Dispose();
                        image.Dispose();
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            return myfile;
        }

        public ActionResult About()
        {
            ViewBag.Message = "Your application description page.";

            return View();
        }

        public ActionResult Contact()
        {
            ViewBag.Message = "Your contact page.";

            return View();
        }
    }
}

3. For we use large images for resizing so we need following settings on web.config file.
   1. 
   2. 
   3. Sometimes we face an issue with garbage collection and memory when we upload large size of images so we use the following things to remove garbage collection and other space.

GC.Collect();
GC.WaitForPendingFinalizers();

4. Currently, I was store resized image in a folder so first create one folder in our solution where we need to store resized images.Note:- In this article, we store resized images on our server but if we need to store resized images on the cloud then please refer to my next article “ Upload Multiple Images In Azure Blob Storage ”.
5. Create Action in Controller where we call the “ResizeImage()” function.

public ActionResult UploadImageThumb(HttpPostedFileBase fileToUpload)
{
	string myfile = ResizeImage(fileToUpload);
	return RedirectToAction("Index", new { imgName = myfile });
}

public ActionResult Index(string imgName)
{
	ViewBag.ImgName = imgName;
	return View();
}

Example:

The source code shown in this article can be downloaded from here:

https://github.com/prajapatichintan/Resize-Large-Image-With-Good-Quality