Drawing on a TImage canvas

Im using the TImage component in an app and I want to know the mouse
state on the mouse move event.  The mousedown and the mouseup events
have Button: TMouseButton to tell me what state the mouse is in.

I know that I can set a flag in the mousedown event and then reset he
flag in the mouse up event. BUT thats not what I want to do.

Can anyone tell me if I can derive my own Timage type with a mouse
move
event that will report a TMouseButton variable.

Any help would be greatly appreciated.

Thanks in advance.