L1=imread('portrait.jpg');
figure,imshow(L1)
title('original')
L2 = L1/5;
 figure, imshow(L2)
 title('dark')
 figure, histogram(L2)
 title('dark hist')
 L3 = L1*2;
 figure, imshow(L3)
 title('Lighten')
 figure,imhist(L3)
 title('Lighten hist')