BCGControlBar Pro for MFC
UINT BCGM_ON_DRAW_TOOLTIP_IMAGE

The message is sent to the parent of CBCGPToolTipCtrl object.

Parameters
wParama handle to Device Content (HDC) where a custom image (icon) is rendered .
lParama pointer to CRect object which contains a tooltip image bounding rectangle.
Returns
The return value is ignored.

You should process this message if you wish to draw a custom image (icons) on the tooltip control.