How to: Change the Appearance of the Windows Forms TabControl
You can change the appearance of tabs in Windows Forms by using properties of the TabControl and the TabPage objects that make up the individual tabs on the control. By setting these properties, you can display images on tabs, display tabs vertically instead of horizontally, display multiple rows of tabs, and enable or disable tabs programmatically.
To display an icon on the label part of a tab
Add an ImageList control to the form.
Add images to the image list.
For more information about image lists, see ImageList Component (Windows Forms) and How to: Add or Remove Images with the Windows Forms ImageList Component.