Clicking A Button With An Icon

[Bridger Maxwell]

Hey,
  I noticed that the mouseUp message is not sent to an image when the user
clicks on a part of the image that is transparent.  However, when the user
clicks on a transparent-type button with its icon set to the same image, the
mousUp message is sent regardless of the transparency of the pixel.  Is
there any way to apply that behavior of the image to the button?  Right now
I have a set of icons that are all 32 x 32, but if the actual colored
portion of the icon is smaller (which it often is), I don't want the button
the receive the mouseUp message.  Is there a way to do this?  Another
possible solution would be to resize the buttons according to the size of
the painted portion of the icon, but I don't know if that is possible
either.

  TTFN
    Bridger