matlab - recover image by only magnitude of image fourier transform

I have a image and I want calculate fft2 of it, after it I want recover image only by magnitude of it. how can I achieve this work?

I=imread('1.bmp');

I = rgb2gray(I);
imafft = fft2(double(I));

 % Gets magnitude and phase.
 mag = abs(imafft);

 % Generates the modified spectrum
 newfft = mag.*exp(0*angle(imafft));
 ima_out = ifft2(newfft);
 imshow(abs(ima_out));

this is return me white page.