>将ImageList添加到您的表单.
>将TabControl的ImageList属性设置为包含图标的ImageList.
>将TabControl中每个TabPage的ImageIndex或ImageKey属性设置为要显示的所需图像.

如果你想在代码中做所有这一切,这里是如何去做的.

using System.Drawing;
using System.Windows.Forms;

public class Form1
{

    public void Form1()
    {
        InitializeComponent();

        // initialize the imagelist
        ImageList imageList1 = new ImageList();
        imageList1.Images.Add("key1",Image.FromFile(@"C:\path\to\file.jpg"));
        imageList1.Images.Add("key2",Image.FromFile(@"C:\path\to\file.ico"));

        //initialize the tab control
        TabControl tabControl1 = new TabControl();
        tabControl1.Dock = DockStyle.Fill;
        tabControl1.ImageList = imageList1;
        tabControl1.TabPages.Add("tabKey1","TabText1","key1"); // icon using ImageKey
        tabControl1.TabPages.Add("tabKey2","TabText2",1);      // icon using ImageIndex
        this.Controls.Add(tabControl1);
    }
}