error while reconstructing an image showing white blank spaces while imshow

I have trained few images in Artificial Neural network using back propogation algorithm and when i try to look back them using the following code,

for
...
  % im = reshape(image(:,xx),row,col/3,3);
  figure;
   imshow(im)
....
end

i am getting a figure with white blank image. I have also tried using imshow(im,[]). But when i use im = reshape(image(:,xx),row,col); i am getting an image in 3 different component. But when i combine using im = reshape(image(:,xx),row,col/3,3) it appears as a white blank figure.

I didn't know the mistake. kindly help me out. thanks in advance.

[Image Analyst]

What is the class and min and max values of im? Can you attach it in a .mat file?