slides[1]= new slide("../../book3/slide1.jpg","","")
slides[2]= new slide("../../book3/slide2.jpg","","")
slides[3]= new slide("../../book3/slide3.jpg","","")
slides[4]= new slide("../../book3/slide4.jpg","","")
slides[5]= new slide("../../book3/slide5.jpg","","")