wxPython 写桌面用到透明图片 透明部分显示时以白色遮挡了背景，应该怎么解决

self.mincol = wx.StaticBitmap(panel, wx.ID_ANY,
wx.Bitmap("./static_src/image/bg_blue_small.png", wx.BITMAP_TYPE_ANY))
self.mincol.SetPosition((0, 0))
font = wx.Font(8, wx.DEFAULT, wx.NORMAL, wx.LIGHT)

self.mincol1 = wx.StaticBitmap(panel, wx.ID_ANY,
wx.Bitmap("./static_src/image/logo_small.png", wx.BITMAP_TYPE_ANY))

    self.mincol1.SetPosition((15, 13))

问题截图

http://bbs.chinaunix.net/thread-842143-1-1.html