docs-desktop/dotnet-desktop-guide/framework/winforms/advanced/how-to-create-thumbnail-images.md

title, ms.date, dev_langs, helpviewer_keywords, ms.assetid

title	ms.date	dev_langs	helpviewer_keywords	ms.assetid
How to: Create Thumbnail Images	03/30/2017	csharp vb	thumbnail images [Windows Forms], creating images [Windows Forms], creating thumbnails	e956242a-1e5b-4217-a3cf-5f3fb45d00ba

How to: Create Thumbnail Images

A thumbnail image is a small version of an image. You can create a thumbnail image by calling the xref:System.Drawing.Image.GetThumbnailImage%2A method of an xref:System.Drawing.Image object.

Example

The following example constructs an xref:System.Drawing.Image object from a JPG file. The original image has a width of 640 pixels and a height of 479 pixels. The code creates a thumbnail image that has a width of 100 pixels and a height of 100 pixels.

The following illustration shows the thumbnail image:

Note

In this example, a callback method is declared, but never used. This supports all versions of GDI+.

[!code-csharpSystem.Drawing.WorkingWithImages#71] [!code-vbSystem.Drawing.WorkingWithImages#71]

Compiling the Code

The preceding example is designed for use with Windows Forms, and it requires xref:System.Windows.Forms.PaintEventArgs e, which is a parameter of the xref:System.Windows.Forms.Control.Paint event handler. To run the example, follow these steps:

1. Create a new Windows Forms application.

2. Add the example code to the form.

3. Create a handler for the form's xref:System.Windows.Forms.Control.Paint event

4. In the xref:System.Windows.Forms.Control.Paint handler, call the GetThumbnail method and pass e for xref:System.Windows.Forms.PaintEventArgs.

5. Find an image file that you want to make a thumbnail of.

6. In the GetThumbnail method, specify the path and file name to your image.

7. Press F5 to run the example.

   A 100 by 100 thumbnail image appears on the form.

See also

• Images, Bitmaps, and Metafiles
• Working with Images, Bitmaps, Icons, and Metafiles