L1=imread('portrait.jpg');
L1 = double(L1)/255;
figure;
imshow(L1);
original = L1;
while 1
 wyb = menu('Menu','Add random','Subtract random','Logarithm','Square root',...
'Power','Original image','Exit');
 switch wyb
 case 1
 L1 = L1 + rand(1);
 imshow(L1);
 case 2
 L1 = L1 - rand(1);
 imshow(L1);
 case 3
 L1=log(L1+1);
 imshow(L1);
 case 4
 L1 = sqrt(L1);
 imshow(L1);
 case 5
 L1 = L1.^3;
 imshow(L1);
 case 6
 L1 = original;
 imshow(L1);
 case 7
 close
 break
 end
end