[Asinkrit]

Держи, функция для определения коллизии двум картинок (TImage).

Код:

function IsCrossImages(const aImage1, aImage2:TImage):boolean;
begin
  with aImage1 do
    Result:=((aImage2.Left >= Left) and (aImage2.Top >= Top) and
             (aImage2.Left <= Left+Width) and (aImage2.Top <= Top+Height))
            or ((aImage2.Left+aImage2.Width >= Left) and (aImage2.Top+aImage2.Height >= Top) and
                (aImage2.Left+aImage2.Width <= Left+Width) and (aImage2.Top+aImage2.Height <= Top+Height))
            or ((aImage2.Left >= Left) and (aImage2.Top+aImage2.Height >= Top) and
                (aImage2.Left <= Left+Width) and (aImage2.Top+aImage2.Height <= Top+Height))
            or ((aImage2.Left+aImage2.Width >= Left) and (aImage2.Top >= Top) and
                (aImage2.Left+aImage2.Width <= Left+Width) and (aImage2.Top <= Top+Height));
end;

Пример использования (в твоем случае):

Код:

   Image4.Visible:=IsCrossImages(Image3,Image4);