how to compress an image using huffman coding ?

img= imread('C:\Users\Islam\Desktop\ball2.jpg');

Image = rgb2gray(img);

Image = Image(:);

[N M] = size(Image)

Count = zeros(256,1)

for i = 1:N

for j = 1:M

Count(Image(i,j)+1)=Count(Image(i,j)+1)+1;

end

end

prob = Count/(M*N)

symbols = 0:255;

[dict,avglen] = huffmandict(symbols,prob);

comp = huffmanenco(Image,dict)

imshow(img);