Create Thumbnail Images In C#

A thumbnail is a small sized image. Creating a thumbnail using .NET is extremely simple. In this article, we will explore how to create a thumbnail image and display the thumbnail in our application. Follow these steps:

1. First Add Windows Form In your Application. After that Drag & drop 1 Label ,  1 TextBox , 2 Buttons , 1 PictureBox & 1 OpenfileDialogBox Controls From Toolbox. Now change all the names of the controls that mention belowed.

   1: TextBox Name = 'txtPath'

   2: 1st Button Name = 'btnOpen'

   3: 2nd Button Name = 'btnGenerate'

   4: PictureBox Name = 'picthumb' And Set Height & Width = 100,100

2. After renaming All the controls On the ‘btnOpen’ click display the File Open dialog box and accept the selected .jpg file in the ’txtPath’ textbox.

   1: private void btnOpen_Click(object sender, EventArgs e)

   2:         {

   3:             if (openFileDialog1.ShowDialog().ToString() == "OK")

   4:             {

   5:                 txtPath.Text = openFileDialog1.FileName;   

   6:             }

   7:         }

3. Next, on the ‘btnGenerate’ click, add the following code:

   1: private void btnGenerate_Click(object sender, EventArgs e)

   2:         {

   3:             Image Img = null;

   4:             Img = Image.FromFile(txtPath.Text);

   5:             Image ImgThumbs = Img.GetThumbnailImage(100, 100, null, new IntPtr());

   6:             if (ImgThumbs != null)

   7:             {

   8:                 picthumb.Image = ImgThumbs;

   9:             }   

  10:         }

The code creates an Image object from the image supplied in the textbox. Using the Image.GetThumbnailImage(), the code then creates a thumbnail image with a size of 100*100.
The Image.GetThumbnailImage() takes in four arguments :


   1: Width : in pixel of the thumbnail image that is to be generated

   2: Height : in pixel of the thumbnail image that is to be generated

   3: Callback : a Image.GetTumbnailImageAbort delegate to prematurely cancel execution

   4: CallbackData : of type IntPtr to represent a pointer or a handl