[im1,map1] = imread('change1.gif');
[im2,map2] = imread('change2.gif');

im_diff = imdivide(im1,im2);
imshow(im_diff)
colormap(map1)
max(im_diff(:))
% ans = 
%      5
min(im_diff(:))
% ans = 
%      0

imshow(im_diff)
colormap(map1)
set(gca,'clim', [0 5])