color image encryption; I have tried this code for color image encryption. the same code is tried for decryption but error occurs,because dimension exceeds!!

I=double(imread('baboon .tiff'));
randomSequence  = round(rand(512,512)*255);
% Encryption by bitxor with psuedo random sequence
for k=1:3

eI = bitxor(I(:,:,k),randomSequence);
end
figure(1);
imshow(uint8(eI));