Tak uz jsem to vyresil, jednoduche jak facka a ja to delam pres object

if not Assigned(bmp3) then
  bmp3:=TBitmap.Create;
bmp3.Assign(bmp1);
duch.BlendOp:=AC_SRC_OVER;
duch.BlendFlags:=0;
duch.SourceConstantAlpha:=Alpha;
duch.AlphaFormat:=0;

AlphaBlend(bmp3.Canvas.Handle,0,0,bmp3.Width,bmp3.Height,
   bmp2.canvas.handle,0,0,bmp2.Width,bmp2.Height,duch);