See this code
public frmForm()
{
InitializeComponent();
tabControl1.Appearance = TabAppearance.Buttons;
tabControl1.DrawMode = TabDrawMode.OwnerDrawFixed;
tabControl1.DrawItem += new DrawItemEventHandler(tabControl1_DrawItem);
}
private void tabControl1_DrawItem(object sender, DrawItemEventArgs e)
{
Image img = Image.FromFile(String.Format("{0}\\{1}.jpg",Application.StartupPath,tabControl1.TabPages[e.Index].Name));
img = new Bitmap(img, e.Bounds.Size);
e.Graphics.DrawImage(img, e.Bounds.Location);
}