How can I change the background-color outside the area of the picture in BackgroundStyle "iebsPhotolike":

If I would use this:
procedure TF_ieLayerTempl.ievpicDrawBackground(Sender: TObject;
  ACanvas: TCanvas; ARect: TRect; var Handled: Boolean);
begin
  Acanvas.Brush.Color := clGray;
  ACanvas.FillRect(ARect);
  Handled := True;
end;
That would fill the whole backround, also of the image (and it would be an unneccessary drawing action).
So how can I change only the color around the image in style "iebsPhotolike"?
HS