CTreeCtrl不能显示节点图片！

在一个窗口上显示CTreeCtrl时，不能显示节点图片.下面是一个图片高：32，共12个小图。每个宽度也是32.请大家帮帮忙。谢谢！


BOOL CConfigDialog::OnInitDialog()
{
    CDialog::OnInitDialog();
   
    // TODO: Add extra initialization here


    DWORD dwStyle = GetWindowLong(m_tree.m_hWnd,GWL_STYLE);
    dwStyle |= TVS_HASBUTTONS | TVS_HASLINES | TVS_LINESATROOT;
    SetWindowLong(m_tree.m_hWnd,GWL_STYLE,dwStyle);

    CImageList imageList;
    CBitmap treeBitmap;
    BOOL success=imageList.Create(CONFIG_ICON_HEIGHT, CONFIG_ICON_WIDTH,  ILC_COLOR8|ILC_MASK , CONFIG_ICON_CNT, CONFIG_ICON_ADD);
    BOOL loadSuccess=treeBitmap.LoadBitmap(IDB_BITMAP_CONFIG);
    int index=imageList.Add(&treeBitmap,RGB(255,255,255));
    CImageList *pOldList=m_tree.SetImageList(&imageList,TVSIL_NORMAL);
    HTREEITEM hItem;
    hItem = m_tree.InsertItem("Directories",0,0,TVI_ROOT);
    return TRUE;  // return TRUE unless you set the focus to a control
                  // EXCEPTION: OCX Property Pages should return FALSE
}